Difference between revisions of "O-Saft/Documentation"

Revision as of 21:02, 12 September 2019

O-Saft

This is O-Saft's documentation as you get with:

o-saft.pl --help

On Windows following must be used

o-saft.pl --help --v

1 O-Saft

NAME

o-saft.pl - OWASP SSL advanced forensic tool

OWASP SSL audit for testers

DESCRIPTION

This tools lists information about remote target's SSL certificate

and tests the remote target according given list of ciphers.

Note: Throughout this description $0 is used as an alias for the

program name o-saft.pl .

SYNOPSIS

 o-saft.pl [COMMANDS ..] [OPTIONS ..] target [target target ...]

Where [COMMANDS] and [OPTIONS] are described below and target

is a hostname either as full qualified domain name or as IP address.

Multiple commands and targets may be combined.

All commands and options can also be specified in a rc-file, see

RC-FILE below.

I.g. all commands start with a + character and options start with

- or -- characters. Anything else is treated as target name.

QUICKSTART

Before going into a detailed description of the purpose and usage,

here are some examples of the most common use cases:

Show supported (enabled) ciphers of target:

   o-saft.pl +cipher --enabled example.tld

Show supported (enabled) ciphers with their DH parameters:

   o-saft.pl +cipher-dh example.tld

Test all ciphers, even if not supported by local SSL implementation:

   o-saft.pl +cipherall example.tld

Show details of certificate and connection of target:

   o-saft.pl +info example.tld

Check certificate, ciphers and SSL connection of target:

   o-saft.pl +check example.tld

Check connection to target for vulnerabilities:

   o-saft.pl +vulns example.tld

Check for all known ciphers (independant of SSL library):

   o-saft.pl example.tld --range=full
   checkAllCiphers.pl example.tld
   checkAllCiphers.pl example.tld --range=full --v

Get the certificate's Common Name for a bunch of servers:

   o-saft.pl +cn example.tld some.tld other.tld

List more usage examples

   o-saft.pl --help=examples

List all available commands:

   o-saft.pl --help=commands

Get table of contents for complete help

   o-saft.pl --help=toc

Show just one section, for example SECURITY, from help

   o-saft.pl --help=SECURITY

Show all --help=* commands

   o-saft.pl --help=HELP

Search for text in O-Saft's help and show with context

   o-saft -help=your-text

Start the simple GUI

   o-saft.tcl

Start the simple GUI which uses o-saft.pl in a Docker image

   o-saft.tcl --docker

For more specialised test cases, refer to the COMMANDS and OPTIONS

sections below. For more examples please refer to EXAMPLES section.

For more details, please see INSTALLATION below.

WHY?

Why a new tool for checking SSL security and configuration when there

are already a dozen or more such good tools in existence (in 2012)?

Unique features:

working in closed environments, i.e. without internet connection
checking availability of ciphers independent of installed library
checking for all possible ciphers (up to 65535 per SSL protocol)
mainly same results on all platforms.

Currently available tools suffer from some or all of following issues:

lack of tests of unusual SSL certificate configurations
may return different results for the same checks on a given target
missing tests for modern SSL/TLS functionality
missing tests for specific, known SSL/TLS vulnerabilities
no support for newer, advanced, features e.g. CRL, OCSP, EV
limited capability to create your own customised tests

Other reasons or problems are that other tools are either binary or

use additional binaries and hence not portable to other platforms.

In contrast to (all?) most other tools, including openssl, it can be

used to `ask simple questions' like `does target support STS' just by

calling:

   o-saft.pl +hsts_sts example.tld

For more, please see EXAMPLES section below.

If it should run on systems with old software (perl or Perl modules),

please see DEBUG section below.

SECURITY

This tool is designed to be used by people doing security or forensic

analyses. Hence no malicious input is expected.

There are no special security checks implemented. Some parameters are

roughly sanatised according unwanted characters. In particular there

are no checks according any kind of code injection.

Care should be taken, when additional tools and modules are installed

as described in INSTALLATION below. In particular it is recommended

to do these installations into directoies specially prepared for use

with o-saft.pl . No other tools of your system should use these installations

i.e. by accident or because your environment variables point to them.

Note that compilation and installation of additional tools (openssl,

Net::SSLeay, etc.) uses known insecure configurations and features!

This is essential to make o-saft.pl able to check for such insecurities.

It is highly recommended to do these installations and use the tools

on a separate testing system.

DO NOT USE THESE INSTALLATIONS ON PRODUCTIVE SYTEMS.

CONCEPTS

The purpose of O-Saft is to do the work, not to force the user to

learn a new tool or to install "newer" software first.

However, the user "should do something" if necessary depending on the

reported results.

Results

Results of checks are marked yes or no. This leaves the proper

interpretation, if the result is "good" or "bad", to the user.

Background: it is not always possible to rate a result as "good" or

"bad" or "insecure" or whatever. That's why O-Saft can not give the

"the best" or a "proper" recomendation. In practice it depends on the

context what a recomendation, or countermeasure should be. That's why

all results are marked yes or no if considered "questionable"

or "not good" (for example according other checks).

... more comming soon ...

TECHNICAL INFORMATION

It is important to understand, which provided information is based on

data returned by underlaying (used) libraries and the information

computed directly.

OpenSSL, libssl, libcrypto

In general the tool uses Perl's Net::SSLeay(3pm) module which itself

is based on libssl and/or libssleay library of the operating system.

It's possible to use other versions of these libraries, see options:

--exe-path=PATH --exe=PATH
--lib-path=PATH --lib=PATH
--envlibvar=NAME

The external openssl(1) is called to extract some information from

its output. The version of openssl can be controlled with following

options:

--openssl=TOOL
--no-openssl
--force-openssl
--exe-path=PATH --exe=PATH

Above applies to all commands except +cipherall and +cipherraw which

uses no other libraries.

OpenSSL is recommended to be used for libssl and libcrypto. Versions

0.9.8k to 1.0.2e (Jan. 2016) are known to work. However, versions be-

for 1.0.0 may not provide all informations.

Some functionality (checks) of O-Saft may be missing or fail, when

openssl versions 1.1.x are used (because functionality was removed).

LibreSSL is not recommended, because some functionallity considered

insecure, has been removed.

For more details, please see INSTALLATION below.

Certificates and CA

All checks according the validity of the certificate chain are based

on the root CAs installed on the system. Note that Net::SSLeay(3pm)

and openssl(1) may have their own rules how and where to find the

root CAs. Please refer to the documentation on your system for these

tools. However, there are folloing options to tweak these rules:

--ca-file=FILE
--ca-path=DIR
--ca-depth=INT

Commands and options

All arguments starting with + are considered COMMANDS for this

tool. All arguments starting with -- are considered OPTIONS for

this tool.

Reading any data from STDIN or here-documents is not yet supported.

It's reserved for future use.

Environment variables

Following environment variables are incorporated:

OPENSSL - if set, full path to openssl executable
OPENSSL_CONF - if set, full path to openssl's openssl.cnf or

directory where to find openssl.cnf

LD_LIBRARY_PATH - used and extended with definitions from options

Requirements

For checking all ciphers and all protocols with +cipherall command,

just perl (5.x) without any modules is required.

For +info and +check (and all related) commands, perl (5.x) with

following modules (minimal version) is required:

IO 1.25 (2011)
IO::Socket:INET 1.37 (2011)
IO::Socket:SSL 1.90 (2013)
Net::DNS 0.66 (2011)
Net::SSLeay 1.49 (2012)

However, it is recommended to use the most recent version of the mod-

ules which then gives more accurate results and less warnings. If the

modules are missing, they can be installed i.e. with:

  cpan Net::SSLeay

Note: if you want to use advanced features of openssl or Net::SSLeay,

please see INSTALLATION section how to compile and install the tools

fully customized.

Also an openssl executable should be available, but is not mandatory.

For checking DH parameters of ciphers, openssl 1.0.2 or newer should

be available. If an older version of openssl is found, we try hard to

extract the DH parameters from the data returned by the server, see

+cipher-dh command.

If you need to run on systems with older perl or Perl module versions

please refer to the DEBUG section for more inofrmation.

RESULTS

All output is designed to be easily parsed by postprocessors. Please

see OUTPUT section below for details.

For the results, we have to distinguish those returned by +cipher

command and those from all other tests and checks like +check or

+info command.

+cipher

The cipher checks will return one line for each tested cipher. It

contains at least the cipher name, yes or no whether it's

supported or not, and a security qualification. It may look like:

   AES256-SHA       yes    HIGH
   NULL-SHA         no     weak

Depending on the used --legacy=* option the format may differ

and also contain more information. For details see --legacy=*

option below.

The text for security qualifications are mainly those returned by

openssl (version 1.0.1): LOW, MEDIUM, HIGH and WEAK.

The same texts but with all lower case characters are used if the

qualification was adapted herein. Following rules for adjusting the

qualification were used:

weak:
- all *NULL* ciphers
- all *RC4* ciphers
- all *EXPORT* ciphers
- all *anon* (aka ADH aka DHA) ciphers
- all *CBC* and *CBC3* (aka 3DES) ciphers
low:
high:
- all *AES(128|256)* ciphers
- all *CAMELLIA* ciphers

+check

These tests return a line with a label describing the test and a

test result for it. The idea is to report yes if the result

is considered "secure" and report the reason why it is considered

insecure otherwise. Example of a check considered secure:

       Label of the performed check:           yes

Example of a check considered insecure:

       Label of the performed check:           no (reason why)

Note that there are tests where the results appear confusing when

first viewed, like for www.wi.ld:

       Certificate is valid according given hostname:  no (*.wi.ld)
       Certificate's wildcard does not match hostname: yes

This can for example occur with:

       Certificate Common Name:                *.wi.ld
       Certificate Subject's Alternate Names:  DNS:www.wi.ld

Please check the result with the +info command also to verify

if the check sounds reasonable.

+info

The test result contains detailed information. The labels there

are mainly the same as for the "+check" command.

COMMANDS

There are commands for various tests according the SSL connection to

the target, the targets certificate and the used ciphers.

All commands are preceded by a + to easily distinguish from other

arguments and options. However, some --OPT options are treated as

commands for historical reason or compatibility to other programs.

The most important commands are (in alphabetical order):

+check +cipher +info +http +list +quick +sni +sni_check +version

A list of all available commands will be printed with

   o-saft.pl --help=cmds

The description of all other commands will be printed with

   o-saft.pl --header --help=commands

The summary and internal commands return requested information or the

results of checks. These are described below.

Note that some commands may be a combination of other commands, see:

   o-saft.pl --header --help=intern

The following sub-sections only describe the commands, which do more

than giving a simple information from the target. All other commands

can be listed with:

   $0 --header --help=commands

The final sub-sections Notes about commands describes some notes

about special commands and related commands.

Commands for information about this tool

All these commands will exit after execution (cannot be used together

with other commands).

+ciphers

Show ciphers offered by local SSL implementation.

This commands prints the ciphers in format like openssl ciphers

does. It also accepts the -v and -V option. The --legacy=TYPE

option can be used as described for +list command.

Use +list command for more information according ciphers.

+list

Show all ciphers known by this tool. This includes cryptogrphic

details of the cipher and some internal details about the rating.

In contrast to +ciphers command +list uses TAB characters

instead of spaces to seperate columns. It also prints table header

lines by default.

Different output formats are used for the --legacy option:

--legacy=simple - tabular output of cipher values
--legacy=full - as --legacy=simple but more data
--legacy=openssl - output like with +cipher command
--legacy=ssltest - output like ssltest --list

+VERSION

Just show version and exit.

+version

Show version information for both the program and the Perl modules

that it uses, then exit.

Use --v option to show more details.

+libversion

Show version of openssl.

+quit

Show internal data and exit, used for testing and debugging only.

Please see TESTING below.

Commands to check SSL details

Following (summary, internal) commands are simply a shortcut for

a list of other commands. For details of the list use:

   o-saft.pl --help=intern

+check

Check the SSL connection for security issues. Implies +cipher .

+host +target

Print details about the targets hostname, DNS, etc.

These details are usually printed only for the +check and +info

command, but not for any individual command.

+http

Perform HTTP checks (like STS, redirects etc.).

+info

Overview of most important details of the SSL connection.

Use --v option to show details also, which span multiple lines.

+info--v

Overview of all details of the SSL connection. This is a shortcut

for all commands listed below but not including +cipher.

This command is intended for debugging as it prints some details

from the used Net::SSLinfo module.

+quick

Quick overview of checks. Implies --enabled and --label=short.

+pfs

Check if servers offers ciphers with prefect forward secrecy (PFS)

+protocols

Check for protocols supported by target.

+vulns

Check for various vulnerabilities.

+sts +hsts

Various checks according STS HTTP header.

This option implies --http, means that --no-http is ignored.

+sni

Check for Server Name Indication (SNI) usage.

+sni_check +check_sni

Check for Server Name Indication (SNI) usage and validity of all

names (CN, subjectAltName, FQDN, etc.).

+bsi

Various checks according BSI TR-02102-2 and TR-03116-4 compliance.

+ev

Various checks according certificate's extended Validation (EV).

Hint: use option --v --v to get information about failed checks.

+sizes

Check length, size and count of some values in the certificate.

+s_client

Dump data retrieved from openssl s_client ... call. Should be

used for debugging only.

It can be used just like openssl itself, for example:

        openssl s_client -connect host:443 -no_sslv2

+dump

Dumps internal data for SSL connection and target certificate.

This is mainly for debugging and should not be used together with

other commands (except +cipher).

Each key-value pair is enclosed in #{ and #} .

Using --trace --trace dumps data of Net::SSLinfo too.

+exec

Command used internally when requested to use other libraries.

This command should not be used directly.

Commands to test ciphers provided by target

Beside the description of the commands itself here, please see also

#Notes about commands below.

+cipher

Check target for ciphers, either all ciphers or ciphers specified

with --cipher=* option.

Note that ciphers not supported by the local SSL implementation

are not checked by default, use +cipherall or +cipherraw command for that.

Use --v option to see all ciphers being checked.

+cipherraw

Check target for all possible ciphers.

Does not depend on local SSL implementation.

In contrast to +cipher this command has some options to tweak

the cipher tests, connection results, and some strange behaviours

of the target. See #Options for cipherall and cipherraw command for details.

+cipherall

Same as +cipherraw but ouput format similat to +cipher command.

+cipher-default

Lists the cipher selected by the server for each protocol sometimes

referred to as "default cipher".

For each protocol the two selected ciphers are shown, one returned

by the server if the cipher list in the ClientHello is sorted with

the strongest cipher first, and one returned if the cipher list in

the ClientHello is sorted with strongest cipher last.

See #Notes about commands for details.

+cipher-dh

Checked target for ciphers. All ciphers supported by the server are

printed with their DH or ECDH paramaters (if available).

ciphers.

+cipher-null +null

Check if target accepts NULL ciphers.

+cipher-adh +adh

Check if target accepts ciphers with anonymous key exchange.

+cipher-exp +export

Check if target accepts EXPORT ciphers.

+cipher-cbc +cbc

Check if target accepts CBC ciphers.

+cipher-des +des

Check if target accepts DES ciphers.

+cipher-rc4

Check if target accepts RC4 ciphers.

+cipher-edh +edh

Check if target supports ephemeral ciphers.

+cipher-pfs

Check if target supports ciphers with PFS.

+cipher-strong

Check if target selects strongest cipher.

+cipher-weak

Check if target selects weak cipher (oposite of +cipher-strong).

Discrete commands to test SSL connection and certificate details

Discrete commands, please see:

   o-saft.pl --help=commands

Notes about commands

+cipher vs. +cipherall

+cipher can only check for ciphers - more precise: cipher suites -

provided by the local SSL implementation (i.e. libssl).

+cipherall can check for any cipher, as it just uses the cipher's

integer value in the range 0 .. 65532.

+cipherall vs. +cipherraw

These commands are identical, just the output format is different.

+cipher vs. +cipher-default

Both commands show the default cipher foreach protocol.

+cipher lists a summary of ciphers selected by the server for each

protocol requested by the user (for example by using options like:

--sslv3 --tlsv1 etc.). When the --v option is used, all selected

ciphers for all known protocols are listed. This summary focuses on

counts for various ciphers.

+cipher-default lists the selected cipher by the server for each

protocol.

+cipher-selected vs. +cipher-default

+cipher-selected lists the cipher selected by the server if no particular

protocol was specified and the system's default cipher list is send

in the ClientHello to the server.

+cipher-default lists the selected cipher by the server for each

protocol.

+cipher-strong vs. +cipher-default

+cipher-strong shows the result of the check if strong ciphers are

preferred by the server. It is a check command.

+cipher-default lists the cipher selected by the server for each

protocol. It is a information command.

It is not possible to check if a server uses 'SSLHonorCipherOrder'.

Even if it is used (switched on), it is not possible to check the

specified order of the ciphers.

I. g. it is expected that the order is according the cipher suite's

strength, meaning the most strongest first, and the weakest last.

It does not make sense to use an order where a weak cipher preceeds

a stronger one. Such a (mis-)configuration should be detected.

Having this in mind, the algorithm to detect a proper cipher order

is as simply as follows:

   1. pass sorted cipher list with strongest cipher first
   2. pass sorted cipher list with strongest cipher last

if the server returns the same cipher for both checks, it's assumed

that it prefers to use the most strongest cipher. In this case it's

obvious that 'SSLHonorCipherOrder' is set (exceptions see below).

+cipherall uses a more accurate algorithm to detect the server's

cipher order.

Exceptions:

If either, the server or the client, uses only one cipher suite in

the list, SSLHonorCipherOrder cannot be detected at all.

The same happens, if only one cipher in the client's list matches a

cipher in the server's list.

+extensions vs. +tlsextensions

+extensions shows the "Certificate extensions" and +tlsextensions

will show the TLS protocol extensions.

Use +tlsextdebug to show more informations about the TLS protocol

extensions.

+http2 +spdy +spdy3 +spdy31 +spdy4 +prots

These commands are just an alias for the +protocols command.

+hostname vs. +wildhost vs. +altname vs. +rfc_2818

The commands +cn and +altname print the information stored in

the certificate.

The command +hostname checks if the given hostname matches the CN

value in the certificate. Note that wildcard names in the CN, only

allow to contain one '*'.

The command +wildcard checks if the given hostname does not match

any name specified in the certificate's "subjectAltname". This check

is usefull if the certificate and the configuration must comply to

RFC 6125 or EV certificates.

OPTIONS

All options are written in lowercase. Words written in all capital in

the description here is text provided by the user.

Options for help and documentation

--h

--help

WYSIWYG

--help=help

Show available options to show descriptions (this Options section).

--help=cmds

Show available commands.

--help=commands

Show available commands with short description.

--help=opt

Show available options; short form.

--help=options

Show available options with their description.

--help=checks

Show available checks.

--help=tools

Description of tools around O-Saft, when, where and how to use.

--help=cmd

Show additional and user specified commands.

--help=cfg-cmd

Show additional and user specified commands. Output can be used in

RC-FILE or as option.

--help=check-cfg --help=cfg-check

Show texts used as labels in output for checks (see +check) ready

for use in RC-FILE or as option.

--help=data

Show available informations.

--help=data-cfg --help=cfg-data --help=cfg-info

Show texts used as labels in output for data (see +info) ready

for use in RC-FILE or as option.

--help=hint

Show texts used in hint messages.

--help=hint-cfg --help=cfg-hint

Show texts used in hint messages ready for use in RC-FILE or as

option.

--help=text

Show texts used in various messages.

--help=text-cfg --help=cfg-text

Show texts used in various messages ready for use in RC-FILE or

as option.

--help=legacy

Show possible legacy formats (used as value in --legacy=KEY).

--help=compliance

Show available compliance checks.

--help=intern

Show internal commands.

--help=range

Show list of cipherranges (see #--cipherrange=RANGE--cipherrange=RANGE).

--help=alias

Show alias for commands and options.

--help=pattern

Show list of cipher pattern (used for --cipher=CIPHER).

--help=score

Show score value for each check.

Value is printed in format to be used for --cfg_score=KEY=SCORE.

Note that the sequence of options is important. Use the options

--trace and/or --cfg_score=KEY=SCORE before --help=score.

--help=toc --help=content

Show headlines from help textsUseful to get an overview.

--help=SECTION

Show SECTION from documentation, see --help=toc for a list.

Example:

     o-saft.pl --help=EXAMPLES

--help=regex

Show regular expressions used internally.

--help=gen-html

Show help text in HTML format.

--help=gen-pod

Show help text in POD format.

--help=gen-wiki

Show help text in mediawiki format.

--help=gen-cgi

Generate HTML page with o-saft.cgi as form action..

--help=error --help=warning --help=problem

Show KNOWN PROBLEMS section with description of known error and

warning messages.

--help=FAQ

Show KNOWN PROBLEMS and LIMITATIONS section.

--help=glossar

Show common abbreviation used in the world of security.

--help=links

Show list of URLs related to SSL/TLS.

--help=rfc

Show list of RFC related to SSL/TLS.

--help=todo

Show known problems and bugs.

--help=exit

Show possible --exit=KEY options. Used for debugging only.

--help=program.code

For developers.

Options for all commands (general)

--dns

Do DNS lookups to map given hostname to IP, do a reverse lookup.

--no-dns

Do not make DNS lookups.

Note that the corresponding IP and reverse hostname may be missing

in some messages then.

--host=HOST

Specify HOST as target to be checked. Legacy option.

--port=PORT

Specify target's PORT to be used. Legacy option.

--host=HOST --port=PORT HOST:PORT HOST

When giving more than one HOST argument, the sequence of the given

HOST argument and the given --port=PORT and the given --host=HOST

options are important.

The rule how ports and hosts are mapped is as follows:

* HOST:PORT arguments are used as is (connection to HOST on PORT)

* only HOST is given, then previous specified --port=PORT is used

Note that URLs are treated as HOST:PORT, if they contain a port.

Example:

   o-saft.pl +cmd host-1 --port 23 host-2 host-3:42 host-4

will connect to:

      host-1:443
      host-2:23
      host-3:42
      host-4:23

--proxyhost=PROXYHOST --proxy=PROXYHOST:PROXYPORT

Make all connection to target using PROXYHOST.

Also possible is: --proxy=PROXYUSER:PROXYPASS@PROXYHOST:PROXYPORT

--proxyport=PROXYPORT

Make all connection to target using PROXYHOST:PROXYPORT.

--proxyuser=PROXYUSER

Specify username for proxy authentication.

--proxypass=PROXYPASS

Specify password for proxy authentication.

--proxy=PROXYUSER:PROXYPASS@PROXYHOST:PROXYPORT is also possible.

--starttls

Use STARTTLS command to start a TLS connection via SMTP.

This option is a shortcut for --starttls=SMTP

--starttls=PROT

Use STARTTLS command to start a TLS connection via protocol.

PROT may be any of: SMTP, IMAP, IMAP2, POP3, FTPS, LDAP, RDP, XMPP

For --starttls=SMTP see --dns-mx also to use MX records instead

of host

--starttls-delay=SEC

Number of seconds to wait before sending a packet, to slow down the

STARTTLS requests. Default is 0.

This may prevent blocking of requests by the target due to too much

or too fast connections.

Note: In this case there is an automatic suspension and retry with

a longer delay.

--cgi, --cgi-exec

Internal use for CGI mode only.

Options for SSL tool

--no-rc

Do not read RC-FILE .

--rc

Read RC-FILE if exists, from directory where program was found.

--rc=path/to/FILE

Read RC-FILE path/to/FILE if exists.

--exitcode

The exit status code will be greater 0, if any of following applies:

any check returns no, except if no (<<...>>)
insecure protocols are available
insecure ciphers are supported
ciphers without PFS are supported

In particular, the status code will be the total count of all these

checks. The status code will also be printed at end, like:

   # EXIT 23

Parts of these checks can be diasabled, see --exitcode-* options

below.

Use --v or --exitcode-v to see details about the performed checks.

Functionality implemented experimental, may change in future.

--exitcode-v

Print information about performed checks.

--exitcode-quiet

Do not print status code at end like # EXIT 23.

--exitcode-no-checks

Do not count checks with result 'no' for --exitcode .

--exitcode-no-low --exitcode-no-weak --exitcode-no-medium

Do not count LOW, WEAK or MEDIUM security ciphers for --exitcode .

--exitcode-no-ciphers

Do not count any ciphers for --exitcode .

--exitcode-no-pfs

Do not count ciphers without PFS for --exitcode .

--openssl-s_client --s_client

Use openssl s_slient ... call to retrieve more informations from

the SSL connection. This is disabled by default on Windows because

of performance problems. Without this option (default on Windows !)

following informations are missing:

      compression, expansion, renegotiation, resumption,
      selfsigned, verify, chain, protocols, DH parameters

See Net::SSLinfo for details.

If used together with --trace, s_client data will also be printed

in debug output of Net::SSLinfo.

--no-openssl

Do not use external openssl tool to retrieve informations. Use of

openssl is disabled by default on Windows.

Note that this results in some missing informations, see above.

--openssl=TOOL

TOOL can be a path to openssl executable; default: openssl

--openssl-cnf=FILE --openssl-conf=FILE

FILE path of directory or full path of openssl.cnf

If set, environment variable OPENSSL_CONF will be set to given path

(or file) when openssl(1) is started. Please see openssl's man page

for details about specifying alternate openssl.cnf files.

--openssl-ciphers --force-openssl

Use openssl to check for supported ciphers; default: IO::Socket

This option forces to use openssl s_slient -connect CIPHER .. to

check if a cipher is supported by the remote target. This is useful

if the --lib=PATH option doesn't work (for example due to changes

of the API or other incompatibilities).

--exe-path=PATH --exe=PATH

PATH is a full path where to find openssl.

--lib-path=PATH --lib=PATH

PATH is a full path where to find libssl.so and libcrypto.so

See HACKER's INFO below for a detailed description how it works.

--envlibvar=NAME

NAME is the name of a environment variable containing additional

paths for searching dynamic shared libraries.

Default is LD_LIBRARY_PATH .

Check your system for the proper name, i.e.:

DYLD_LIBRARY_PATH, LIBPATH, RPATH, SHLIB_PATH .

--ssl-error

The connection to a target may fail, or even block, due to various

reasons, for example lost network at all, blocking at firewall, etc.

In particular when checking ciphers with +cipher , this may result

in long delays until results are printed.

Using this option stops trying to do more connections to the target

when --ssl-error-max=CNT consecutive errors occoured, or if the total

amount of errors increases --ssl-error-total=CNT.

--ssl-error-max=CNT

Max. amount of consecutive errors (default: 5).

--ssl-error-timeout=SEC

Timeout in seconds when a failed connection is treated as error and

then counted (default: 1).

--ssl-error-total=CNT

Max. total amount of errors (default: 10).

--ssl-lazy

I.g. this tools tries to identify available functionality according

SSL versions from the underlaying libraries. Unsupported versions

are then disables and a warning is shown.

Unfortunately some libraries have not implemented all functions to

check availability of a specific SSL version, which then results in

a compile error.

This option disables the strict check of availability.

If the underlaying library doesn't support the required SSL version

at all, following error may occour:

      Can't locate auto/Net/SSLeay/CTX_v2_new.al in @INC ...

--timeout=SEC

Timeout in seconds when connecting to the target (default: 2).

-v

Print list of ciphers in style like: openssl ciphers -v.

Option used with +ciphers command only.

-V

Print list of ciphers in style like: openssl ciphers -V.

Option used with +ciphers command only.

Options for SSL connection to target

--cipher=CIPHER

CIPHER can be any string accepeted by openssl or following:
yeast use all ciphers from list defined herein, see +list

Beside the cipher names accepted by openssl, CIPHER can be the name

of the constant or the (hex) value as defined in openssl's files.

Currently supported are the names and constants of openssl 1.0.1k .

Example:

--cipher=DHE_DSS_WITH_RC4_128_SHA
--cipher=0x03000066
--cipher=66

will be mapped to DHE-DSS-RC4-SHA

Note: if more than one cipher matches, just one will be selected.

Default is ALL:NULL:eNULL:aNULL:LOW as specified in Net::SSLinfo

--socket-reuse

TCP socket will be reused for next connection attempt even if SSL

connection failed.

--no-socket-reuse

Close TCP socket and then reopen for next connection attempt if SSL

connection failed.

This is useful for some servers which may return an "TLS alert" if

the connection fails and then fail again on the same socket.

--ignore-no-connect

A simple check if the target can be connected will be performed by

default. If this check fails, the target will be ignored, means no

more reuqested checks will be done. As this connection check some-

times fails due to various reasons, the check can be disabled using

this option.

--no-md5-cipher

Do not use *-MD5 ciphers for other protocols than SSLv2.

This option is only effective with +cipher command.

The purpose is to avoid warnings from IO::Socket::SSL(3pm) like:

        Use of uninitialized value in subroutine entry at lib/IO/Socket/SSL.pm line 430.

which occours with some versions of IO::Socket::SSL(3pm) when a

-MD5 ciphers will be used with other protocols than SSLv2.

Note that these ciphers will be checked for SSLv2 only.

--SSL, -protocol SSL

--no-SSL

SSL can be any of:

ssl, ssl2, ssl3, sslv2, sslv3, tls1,

tls1, tls11, tls1.1, tls1-1, tlsv1, tlsv11, tlsv1.1, tlsv1-1

(and similar variants for tlsv1.2).

For example --tls1 --tlsv1 --tlsv1_1 are all the same.

(--SSL variants): Test ciphers for this SSL/TLS version.

(--no-SSL variants): Don't test ciphers for this SSL/TLS version.

--no-tcp

Shortcut for:

--no-sslv2 --no-sslv3 --no-tlsv1 --no-tlsv11 --no-tlsv12 --no-tlsv13

--tcp

Shortcut for: --sslv2 --sslv3 --tlsv1 --tlsv11 --tlsv12 --tlsv13

--no-udp

Shortcut for:

--no-dtlsv09 --no-dtlsv1 --no-dtlsv11 --no-dtlsv12 --no-dtlsv13

--udp

Shortcut for: --dtlsv09 --dtlsv1 --dtlsv11 --dtlsv12 --dtlsv13

--nullsslv2

This option forces to assume that SSLv2 is enabled even if the

target does not accept any ciphers.

The target server may accept connections with SSLv2 but not allow

any cipher. Some checks verify if SSLv2 is enabled at all, which

then would result in a failed test.

The default behaviour is to assume that SSLv2 is not enabled if no

ciphers are accepted.

--http

Make a HTTP request if cipher is supported.

If used twice debugging will be enabled using environment variable

HTTPS_DEBUG .

--no-http

Do not make HTTP request.

--sni

Make SSL connection in SNI mode.

--no-sni

Do not make SSL connection in SNI mode (default: SNI mode).

--sni-toggle --toggle-sni

Test with and witout SNI mode (+cipherall only).

--force-sni

Do not check if SNI seems to be supported by Net::SSLeay(3pm).

Older versions of openssl and its libries do not support SNI or the

SNI support is implemented buggy. By default it's checked if SNI is

properly supported. With this option this check can be disabled.

Be warned that this may result in improper results.

--servername=NAME

--sni-name=NAME

If in SNI mode is active, see --sni above, NAME is used instead of

hostname for connections to the target. If SNI mode is not active,

see --no-sni above, NAME is not used. The default is undefined,

which forces to use the given FQDN.

This is useful, for example when an IP instead of a FQDN was given,

where a correct hostname (i.g. a FQDN) needs to be specified.

Note: i.g. there is no need to use this option, as a correct value

for the SNI name will be choosen automatically (except for IPs).

However, it is kind of fuzzing ...even setting to an empty string

is possible.

Limitation: the same NAME is used for all targets, if more than

one target was specified.

--no-cert

Do not get data from target's certificate, return empty string.

--no-cert --no-cert

Do not get data from target's certificate, return default string

of Net::SSLinfo (see --no-cert-text TEXT option).

--no-cert-text=TEXT

Set TEXT to be returned from Net::SSLinfo.pm if no certificate

data is collected due to use of --no-cert.

--ca-depth=INT

Check certificate chain to depth INT (like openssl's -verify).

--ca-file=FILE

Use FILE with bundle of CAs to verify target's certificate chain.

--ca-path=DIR

Use DIR where to find CA certificates in PEM format.

--no-nextprotoneg

Do not use -nextprotoneg option for openssl.

--proto-alpn=NAME

Name of protocol to be added to list of applcation layer protocols

(ALPN), which is used for any connection to the targets.

See --cipher-alpn=NAME also.

--proto-npn=NAME

Name of protocol to be added to list of next protocol negotiations

(NPN), which is used for any connection to the targets.

See --cipher-npn=NAME also.

--ssl-compression --compression

Use SSL option "compression" for connection.

--no-ssl-compression --no-compression

Use SSL option "no compression" for connection (default: don't use)

--no-reconnect

Do not use -reconnect option for openssl.

--no-tlsextdebug

Do not use -tlsextdebug option for openssl.

--sclient-opt=VALUE

Argument or option passed to openssl s_client command.

Options for +cipher command

--cipher-alpn=NAME

Name of protocol to be added to list of applcation layer protocols

(ALPN), which is used for cipher checks.

--cipher-alpn=, sets empty list.
--cipher-alpn=,, sets list to empty element "".

--cipher-npn=NAME

Name of protocol to be added to list of next protocol negotiations

(NPN), which is used for cipher checks.

--cipher-lpn=, sets empty list.
--cipher-lpn=,, sets list to empty element "".

Note: setting empty list or element most likely does not work with

openssl executable (i.e. --force-openssl).

--cipher-curve=NAME

Name of ecliptic curve to be added to list of ecliptic curves (EC),

which is used for cipher checks.

--cipher-curve=, sets empty list.
--cipher-curve=,, sets list to empty element "".

Note: setting empty list or element most likely does not work with

openssl executable (i.e. --force-openssl).

Options for cipherall and cipherraw command

--range=RANGE

--cipherrange=RANGE

Specify range of cipher constants to be tested by +cipherall .

Following RANGEs are supported (see also --cipherrange=RANGE):

rfc all ciphers defined in various RFCs
shifted rfc, shifted by 64 bytes to the right
long like rfc but more lazy list of
huge all constants 0x03000000 .. 0x0300FFFF
safe all constants 0x03000000 .. 0x032FFFFF
full all constants 0x03000000 .. 0x0300FFFF
SSLv2 all ciphers according RFC for SSLv2

Note: SSLv2 is the internal list used for testing SSLv2 ciphers.

It does not make sense to use it for other protocols; however ...

--slow-server-delay=SEC

Additional delay in seconds after the server is connected using a

proxy or before starting STARTTLS.

This is useful when connecting via slow proxy chains or connecting

to slow servers before sending the STARTTLS sequence.

--ssl-maxciphers=CNT

Maximal number of ciphers sent in a sslhello (default: 32).

--ssl-double-reneg

Send SSL extension "reneg_info" even if list of ciphers includes

TLS_EMPTY_RENEGOTIATION_INFO_SCSV (default: do not include)

--ssl-nodata-nocipher

Do not abort testing for next cipher when the target responds with

"NoData" times out. Useful for TLS intolerant servers.

By default testing for ciphers is aborted when the target responds

with "noData message.

--ssl-use-ecc

Use supported elliptic curves. Default on.

--ssl-use-ec-point

Use TLS "ec_point_formats" extension. Default on.

--ssl-use-reneg

Test for ciphers with "secure renegotiation" flag set.

Default: don't set "secure renegotiation" flag.

--ssl-retry=CNT

Number of retries when connection timed-out (default: 2).

--ssl-timeout=SEC

Number of seconds to wait until connection is qualified as timeout.

--dns-mx, --mx

Get DNS MX records for given target and check the returned targets.

(only useful with --starttls=SMTP)

Options for checks and results

Options used for +check command:

--enabled

Only print result for ciphers accepted by target.

--disabled

Only print result for ciphers not accepted by target.

--ignorecase

Checks are done case insensitive.

--no-ignorecase

Checks are done case sensitive. Default: case insensitive.

Currently only checks according CN, alternate names in the target's

certificate compared to the given hostname are effected.

--ignore-no-reply

When checking for the TLS "heartbeat" extension, the server may not

respond at all, which would result in a "no reply" message. This

marks the check for +heartbleed as no.

I.g. a server is not vulnerable to the heartbleed attack if the

TLS "heartbeat" extension is disabled. Hence the check result no

may be mis-leading. This option treats the "no reply" result as

"not vulnerable" and returns yes then.

Note: if the server does not respond for this check, does not mean

that the "heartbeat" extension is switched off. If unsure, disable

this lazy check with --no-ignore-no-reply .

Options for output format

--label=TYPE

Defines the format of the descriptive text(label) for +check and

+info command.

Following TYPEs are supported:

--label=long

Prints full text for labels:

 Certificate Common Name:  some.tld

--label=short

Prints short less descriptive text for labels:

 Common Name:              some.tld

--label=key

Internal format: print name of key instead of text as label. Key is

Prints name of key instead of text as label. The key is that of the

internal data structure(s).

 [cn]                      some.tld

--legacy=TOOL

For compatibility with other tools, the output format used for the

result of the +cipher command can be adjusted to mimic the format

of other SSL testing tools.

The argument to the --legacy=TOOL option is the name of the tool

to be simulated.

Following TOOLs are supported:

sslaudit format of output similar to sslaudit
sslcipher format of output similar to ssl-cipher-check
ssldiagnos format of output similar to ssldiagnos
sslscan format of output similar to sslscan
ssltest format of output similar to ssltest
ssltestg format of output similar to ssltest -g
ssltest-g format of output similar to ssltest -g
sslyze format of output similar to sslyze
ssl-cipher-check same as sslcipher
ssl-cert-check format of output similar to ssl-cert-check
testsslserver format of output similar to TestSSLServer.jar
thcsslcHeck format of output similar to THCSSLCheck

Note that these legacy formats only apply to output of the checked

ciphers. Other texts like headers and footers are adapted slightly.

Please do not expect identical output as the TOOL when using these

options, it's a best guess and should be parsable in a very similar

way.

--legacy=TYPE

--legacy=compact

Internal format: mainly avoid tabs and spaces format is as follows:

Some Label:<-- anything right of colon is data

--legacy=full

Internal format: pretty print each label in its own line, followed

by data prepended by tab character (useful for +info only).

--legacy=owasp

Results for cipher checks use rating from OWASP Cipher Cheat Sheet.

--legacy=quick

Internal format: use tab as separator; ciphers are printed with bit

length (implies --tab).

--legacy=simple

Internal default format.

--format=FORM

This option is used to specify the format of the result lines. This

covers the value of the result line only.

raw Print raw data as passed from Net::SSLinfo .

Note: all data will be printed as is, without additional label

or formatting. It's recommended to use the option in conjunction

with exactly one command. Otherwise the user needs to know how

to "read" the printed data.

hex Convert some data to hex: 2 bytes separated by :.
0x Convert some data with hex values:

2 bytes preceded by 0x and separated by a space.

/x Same as --format=\x
\x Convert some data with hex values:

2 bytes preceded by \x and no separating char.

--header

Print formatting header. Default for +check, +info, +quick.

and +cipher only.

--no-header

Do not print formatting header.

Usefull if raw output should be passed to other programs.

Note: must be used on command line to inhibit all header lines.

--ignore-cmd=CMD

--ignore-output=CMD

--no-cmd=CMD

--no-output=CMD

Do not print output (data or check result) for command CMD.

CMD is any valid command, see COMMANDS, without leading +.

Option can be used multiple times.

--score

Print scoring results. Default for +check.

--no-score

Do not print scoring results.

--separator=CHAR

--sep=CHAR

CHAR will be used as separator between label and value of the

printed results. Default is :

--tab

TAB character (0x09, \t) will be used as separator between label

and value of the printed results.

As label and value are already separated by a TAB character, this

options is only useful in conjunction with the --legacy=compact

option.

--showhost

Prefix each printed line with the given hostname (target).

The hostname will be followed by the separator character.

--std-format=utf8

--std-format=crlf

--std-format=raw

--std-format=unix

--std-format=CHARSET

This option is used to specify the general output format for STDOUT

and STDERR. All results are written to STDOUT, errors and warnings

may also be written to STDERR . The default is :unix:utf8, which

is the perlish definition used internally.

Following values are supported:

raw
unix Print raw data, binary in bytes without conversion.

Note: binary here just means characters (as all output is text).

utf8 Convert all characters to UTF-8.
crlf Use CR LF as end of line.

CHARSET CHARSET can be any of the local installed character

sets, like UTF-8, UTF-16LE, CP1252, iso-8859-7, etc..

This conversion may print its own warnings.

The option can be used multiple times with different values.

To reset the default behaviour, either raw or unix must be

used. Obviously, they must be used first. All other values are used

additionally.

Note: utf8 just defines the format of the characters, it does no

further checks on the converted characters. In contrast, UTF-8 is

used as real encoding and does some checks.

For more details, please see "perldoc -f binmode" .

Currently (Jan. 2018), these options must be used before any --help

option.

--win-CR

Obsolete, please use --std-format=crlf .

Options for compatibility with other programs

Please see other programs for detailed description (if not obvious:).

Note that often only the long form options are accepted as most short

form options are ambiguous.

If other programs use the same option,but with a different behaviour,

then thes other options are not supported.

For a list of supported options, please see:

 o-saft.pl --help=alias

Following list contains only those options not shown with:

 o-saft.pl --help=alias

Tool's Option        (Tool)          o-saft.pl Option
--------------------+---------------+---------------------------
 --checks CMD        (TLS-Check.pl)  same as +CMD
 -h, -h=HOST         (various tools) same as --host HOST
 -p, -p=PORT         (various tools) same as --port PORT
 -t HOST             (ssldiagnos)    same as --host HOST
 --protocol SSL      (ssldiagnos)    same as --SSL
 --UDP               (ssldiagnos)    same as --udp
 --insecure          (cnark.pl)      ignored
 --nopct --nocolor   (ssldiagnos)    ignored
 --timeout, --grep   (ssltest.pl)    ignored
 -r,  -s,  -t,  -x   (ssltest.pl)    ignored
 -connect, -H, -u, -url, -U          ignored
 -noSSL                              same as --no-SSL
 -no_SSL                             same as --no-SSL
--------------------+---------------+---------------------------

For definition of SSL see --SSL and --no-SSL above.

Options for customization

For general descriptions please see CUSTOMIZATION section below.

--cfg_cmd=CMD=LIST

Redefine list of commands. Sets %cfg{cmd-CMD} to LIST. Commands

can be written without the leading +.

If CMD is any of the known internal commands, it will be redifned.

If CMD is a unknown command, it will be created.

Example:

   --cfg_cmd=sni=sni hostname

To get a list of commands and their settings, use:

   o-saft.pl --help=intern

Main purpose is to reduce list of commands or to print them sorted.

An example +preload can be found in .o-saft.pl .

--cfg_score=KEY=SCORE

Redefine value for scoring. Sets %checks{KEY}{score} to SCORE.

Most score values are set to 10 by default. Values 0 .. 100 are

allowed.

To get a list of current score settings, use:

   o-saft.pl --help=score

For deatils how scoring works, please see SCORING section.

Use the --trace-key option for the +info and/or +check

command to get the values for KEY.

--cfg_checks=KEY=TEXT --cfg_data=KEY=TEXT

Redefine texts used for labels in output. Sets %data{KEY}{txt} or

%checks{KEY}{txt} to TEXT.

To get a list of preconfigured labels, use:

   o-saft.pl --help=cfg_checks
   o-saft.pl --help=cfg_data

--cfg_text=CIPHER=value

Redefine the security value (i.e. HIGH) in the cipher description.

Example:

   o-saft.pl --cfg-cipher=NULL-MD5=no-security-at-all ...

--cfg_text=KEY=TEXT

Redefine general texts used in output. Sets %text{KEY} to TEXT.

To get a list of preconfigured texts, use:

   o-saft.pl --help=cfg_text

Note that \n, \r and \t are replaced by the corresponding character

when read from RC-FILE.

--cfg_text=FILE

Read definitions for %text{KEY}="my text" from file FILE.

--cfg_hint=KEY=TEXT

Redefine texts used for hints. Sets %cfg{hints}{KEY} to TEXT.

To get a list of preconfigured texts, use:

   o-sat.pl --help=cfg-hint

--call=METHOD

See Options for SSL tool

--usr

Execute functions defined in o-saft-usr.pm.

--usr-*

--user-*

Options ignored, but stored as is internal in $cfg{usr-args} .

These options can be used in o-saft-usr.pm or o-saft-dbx.pm.

--experimental

Use experimental functionality.

Some functionality of this tool is under development and only used

when this option is given.

Options for tracing and debugging

--n --dry-run

Do not execute, just show commands (only useful in conjunction with

using openssl).

Difference --trace vs. --v

While --v is used to print more data, --trace is used to print

more information about internal data such as procedure names and/or

variable names and program flow.

--v

--verbose

Print more information about checks.

Note that this option should be first otherwise some debug messages

are missing.

Note that --v is different from -v (see above).

--v --v

Print remotely checked ciphers.

--v-cipher --cipher-v

Print remotely checked ciphers.

In contrast to --v --v above, this just prints the ciphers while

being checked, but no other verbose messages.

--trace

Print debugging messages.

--trace --trace

Print more debugging messages and pass trace=2 to Net::SSLeay and

Net::SSLinfo.

--trace --trace --trace

Print more debugging messages and pass trace=3 to Net::SSLeay and

Net::SSLinfo.

--trace --trace --trace --trace

Print processing of all command line arguments.

--trace-cli

Print complete command line first. Used for internal testing.

--trace--

--trace-arg

Print command line argument processing.

--trace-cmd

Trace execution of command processing (those given as +*).

--trace@

--trace-key

Print some internal variable names in output texts (labels).

Variable names are prefixed to printed line and enclosed in # .

Example without --trace-key :

      Certificate Serial Number:          deadbeef

Example with --trace-key :

      #serial#          Certificate Serial Number:          deadbeef

--trace=VALUE

Alias for --trace-VALUE options (see above).

Trace Option Alias Option

--trace=1 same as --trace
--trace=2 same as --trace --trace
--trace=arg same as --trace-arg
--trace=cmd same as --trace-cmd
--trace=key same as --trace-key

--trace-time

Prints timestamp in trace output. More timestamps are printed if

used together with --trace-cmd.

--trace=FILE

Use FILE instead of the default RC-FILE, i.e. .o-saft.pl.

--trace-me

Print debugging messages for o-saft.pl only, but not any modules.

--trace-not-me

Print debugging messages for modules only, but not o-saft.pl istself.

--trace-sub +traceSUB

Print formatted list of internal functions with their description.

Not to be intended in conjunction with any target check.

--hint

Print hint messages (!!Hint:).

--no-hint

Do not print hint messages (!!Hint:).

--warning

Print warning messages (**WARNING:).

--no-warning

Do not print warning messages (**WARNING:).

--exit=KEY

Terminate o-saft.pl at specified KEY. Please see TESTING below.

Options vs. Commands

For compatibility with other programs and lazy users, some arguments

looking like options are silently taken as commands. This means that

--THIS becomes +THIS then. These options are:

--help
--abbr
--todo
--chain
--default
--fingerprint
--list
--version

Take care that this behaviour may be removed in future versions as it

conflicts with those options and commands which actually exist, like:

--sni vs. +sni

LAZY SYNOPSIS

Commands

Following strings are treated as a command instead of target names:

ciphers
s_client
version

A warning will be printed.

Options

We support following options, which are all identical, for lazy users

and for compatibility with other programs.

Option Variants

--port PORT

--port=PORT

This applies to most such options, --port is just an example.

When used in the RC-FILE, the --OPTION=VALUE variant must be used.

Option Names

Dash -, dot . and/or underscore _ in option names are optional,

all following are the same:

--no.dns

--no-dns

--no_dns

--nodns

This applies to all such options, --no-dns is just an example.

Targets

Following syntax is supported also:

   o-saft.pl http://some.tld other.tld:3889/some/path?a=b

Note that only the hostname and the port are used from an URL.

Options vs. Commands

See Options vs. Commands in OPTIONS section above

CHECKS

All SSL related check performed by the tool will be described here.

General Checks

Lookup the IP of the given hostname (FQDN), and then tries to reverse

resolve the FQDN again.

SSL Ciphers

Check which ciphers are supported by target. Please see RESULTS for

details of this check.

SSL Connection

heartbeat

Check if "heartbead" extension is supported by target.

poodle

Check if target is vulnerable to POODLE attack (SSLv3 enabled).

robot

Check if target is vulnerable to ROBOT attack (server offers ciphers

with RSA encryption).

sloth

Check if target is vulnerable to SLOTH attack (server offeres RSA-MD5

or ECDSA-MD5 ciphers).

sweet32

Check if target is vulnerable to Sweet32 attack (server offers CBC or

CBC3 or DES or 3DES ciphers).

Note that FIPS-140 compliance requires 3DES ciphers, hence compliant

systems are then vulnerable to Sweet32 attacks.

ALPN

Check if target supports ALPN. Following messages are evaluated:

   ALPN protocol: h2-14
   No ALPN negotiated

Please see also CHECKS ALPN and NPN below.

SSL Vulnerabilities

ADH

Check if ciphers for anonymous key exchange are supported: ADH|DHA .

Such key exchanges can be sniffed.

EDH

Check if ephemeral ciphers are supported: DHE|EDH .

They are necessary to support Perfect Forward Secrecy (PFS).

BEAST

Check if ciphers with CBC for protocol SSLv1, SSLv3 or TLSv1 are used.

TLSv1.2 checks are not yet implemented.

CRIME

Connection is vulnerable if target supports SSL-level compression.

DROWN

Connection is vulnerable if target supports SSLv2 (with at least one cipher).

FREAK

Attack Against SSL/TLS to downgrade to EXPORT ciphers.

Currently (2018) a simple check is used: SSLv3 enabled and EXPORT

ciphers supported by server.

See CVE-2015-0204 and https://freakattack.com/ .

HEARTBLEED

Check if target is vulnerable to heartbleed attack, see CVE-2014-0160

and http://heartbleed.com/ .

HEIST

Not implemented.

There are no checks for the HEIST attack implemented, because this is

an attack on TCP/IP rather than SSL/TLS on top of TCP/IP.

KCI

Not implemented.

To perform a MiTM attack with Key Compromise Impersonation, the atta-

cker needs to engage the victim to install and use a client certificate.

This is considered a low risk and hence not tested here.

Logjam

Check if target is vulenerable to Logjam attack.

Check if target suports EXPORT ciphers and/or DH Parameter is less

than 2048 bits.

Lucky 13

Check if CBC ciphers are offered.

NOTE the recommendation to be safe againts Lucky 13 was to use RC4

ciphers. But they are also subjetc to attacks (see below). Hence the

check is only for CBC ciphers.

RC4

Check if RC4 ciphers are supported.

They are assumed to be broken.

Note that +rc4 reports the vulnerabilitiy to the RC4 Attack, while

+rc4_cipher simply reports if RC4 ciphers are offered. However the

the check, and hence the result, is the same.

PFS

Check if DHE ciphers are used. Also check if the TLS session ticket

is random or not used at all.

Currently (2018) only a simple check is used: only DHE ciphers used.

TLSv1.2 checks are not yet implemented.

POODLE

Check if target is vulnerable to POODLE attack (just check if SSLv3

is enabled).

Practical Invalid Curve Attack

This attack allows an attacker to read the servers private key if the

server does not check properly the passed points for a ecliptic curve

when EDH ciphers are used.

This check will not send multiple invalid points, but only checks if

the server closes the connection or responds with no matching cipher.

ROBOT

Bleichebacher's Oracle attack against SSL/TLS ciphers.

Not implemented.

https://robotattack.org/

SLOTH

Currently (2016) we check for ciphers with ECDSA, RSA-MD5.

Checking the TLS extension 'tls-unique' is not yet implemented.

Sweet32

Currently (2016) we check for ciphers with CBC or CBC3 or DES or 3DES.

Target (server) Configuration and Support

BEAST, BREACH, CRIME, DROWN, FREAK, Logjam, Lucky 13, POODLE, RC4, ROBOT, SLOTH, Sweet32

See above.

Renegotiation

Check if the server allows client-side initiated renegotiation.

Version rollback attacks

NOT YET IMPLEMENTED

Check if the server allows changing the protocol.

DH Parameter

Check if target's DH Parameter is less 512 or 2048 bits.

SSTP

Check if target supports SSTP by accepting method SSTP_DUPLEX_POST.

The check does not send other methods (like CONNECT) to verify if the

protocol is fully supported.

Supporting SSTP is considered insecure, because SSTP allows to tunnel

other, probably insecure, protocols.

Target (server) Certificate

Certificate Hashes

Check that fingerprint is not MD5.

Check that certificate private key signature is SHA2 or better.

Root CA

Provided certificate by target should not be a Root CA.

Self-signed Certificate

Certificate should not be self-signed.

FQDN is listed in subjectAltname (RFC2818)

The FQDN must be listed in the certificates subjectAltname.

The check command +rfc_2818_names is based on the info command

+verify_hostname . The check was added in 05/2017 because browsers

started to complain if the FQDN is not part of the subjectAltname.

IP in CommonName or subjectAltname (RFC6125)

NOT YET IMPLEMENTED

Basic Constraints

Certificate extension Basic Constraints should be CA:FALSE.

OCSP, CRL, CPS

Certificate should contain URL for OCSP and CRL.

Private Key encyption

Certificates signature key supports encryption.

Private Key encyption well known

Certificates signature key encryption algorithm is well known.

Public Key encyption

Certificates public key supports encryption.

Public Key encyption well known

Certificates public key encryption algorithm is well known.

Public Key Modulus size

Some (historic) SSL implementations are subject to buffer overflow if

the key exceeds 16384 or 32768 bits. The check is against 16384 bits.

Public Key Modulus Exponent size

The modulus exponent should be = 65537 as it is a prime number and an

easy to calculate exponent.

If the exponent is less than 65537, "Boradcast" attacks are possible.

However, some (mainly historic) SSL implementations may have problems

to connect because they are not able to do the crypt mathematics with

exponenents larger than 65536.

If ecliptic curves are used, the result for these checks is always

no (<<N/A ...).

Sizes and Lengths of Certificate Settings

Serial Number <= 20 octets (RFC5280, 4.1.2.2. Serial Number)

...

DV-SSL - Domain Validation Certificate

The Certificate must provide:

Common Name /CN= field
Common Name /CN= in subject or subjectAltname field
Domain name in commonName or altname field

EV-SSL - Extended Validation Certificate

This check is performed according the requirements defined by the CA/

Browser Forum https://www.cabforum.org/contents.html .

The Certificate must provide:

DV - Domain Validation Certificate (see above)
Organization name /O= Cn subject field
Organization name must be less to 64 characters
Business Category /businessCategory= in subject field
Registration Number /serialNumber= in subject field
Address of Place of Business in subject field

Required are: /C=, /ST=, /L=

Optional are: /street=, /postalCode=

Validation period does not exceed 27 month

See LIMITATIONS also.

Target (server) HTTP(S) Support

STS header (see RFC 6797)

Using STS is no perfect security. While the very first request using

http: is always prone to a MiTM attack, MiTM is possible to following

requests again, if STS is not well implemented on the server.

Request with http: should be redirected to https:
Redirects should use status code 301 (even others will work)
Redirect's Location header must contain schema https:
Redirect's Location header must redirect to same FQDN
Redirect may use Refresh instead of Location header (not RFC6797)
Redirects from HTTP must not contain STS header
Answer from redirected page (HTTPS) must contain STS header
Answer from redirected page for IP must not contain STS header
STS header must contain includeSubDirectoy directive
STS header max-age should be less than 1 month
STS must not be set in http-equiv attribute of a meta TAG

STS header preload attribute (+preload)

To satisfy the requirements on https://hstspreload.appspot.com/ the

HSTS header must:

have the max-age with at least 18 weeks (10886400 seconds)
have the includeSubDomains attribute
have the preload attribute
redirect to https first, then to sub-domains (if redirected)
have an HSTS header in each redirect to https.

Additionally, the site must have:

a valid certificate
serve all subdomains over https.

Except the last requirement, +preload will do the checks.

Note that +preload is defined in .o-saft.pl only.

Public Key Pins header

TBD - to be described ...

Sizes

Mainly in the certificate various counts, lengths and sizes of values

are checked and reported. All commands for these checks start with

+cnt_ or +len_. Up to now, there is no yes or no value

for these checks.

Following commands will check the value to be in a specific range to

become yes or no:

+sts_maxage1d - yes if HSTS maxage < 1 day
+sts_maxage1m - yes if HSTS maxage < 1 month
+sts_maxage1y - yes if HSTS maxage < 1 year
+sts_maxage18 - yes if HSTS maxage < 18 weeks (5 months)
+sts_maxagexy - yes if HSTS maxage > 1 year
+modulus_exp_1 - Public Key Modulus Exponent <>1
+modulus_exp_65537 - Public Key Modulus Exponent =65537
+modulus_exp_oldssl - Public Key Modulus Exponent <65537
+modulus_size_oldssl - Public Key Modulus <16385 bits

For some details of these checks, please see the description above at

"Public Key Modulus Exponent size"

The recommendations for DH parameters (RSA and ecliptice curve) are

are checked as follows:

+dh_512 - DH Parameter >= 512 bits
+dh_2048 - DH Parameter >= 2048 bits
+ecdh_256 - DH Parameter >= 256 bits (ECDH)
+ecdh_512 - DH Parameter >= 512 bits (ECDH)

Note that only one of the checks +dh_* and +ecdh_* can return

yes.

ALPN and NPN

The commands for the checks to report yes or no, are +hasalpn

and +hasnpn.

Both, the Application Layer Protocol Negotiation (ALPN) and the Next

Protocol Negotiation (NPN) will be tested. The commands for that are:

+alpns
+npns

Each, ALPN and NPN, is tested separately with all known protocols.

The test sets only one protocol, tries to make a connection and then

checks if the protocol was accepted by the server. The collected list

of protocols will be printed with the aforementioned commands, or the

+info command. Note the difference for the commands +next_protocols

and +alpns, where +next_protocols simply reports what the server

itself advertises, while +alpns reports what the server supports if

asked for.

Compliances

Note that it is not possible to satisfy all following compliances. Best

match is: PSF and ISM and PCI and lazy BSI TR-02102-2.

In general it is difficult to satisfy all conditions of a compliances,

and it is also difficult to check all these conditions. That's why some

of the compliances checks are not completely implemented, for details

please see blow.

Note that output of results of some checks is disabled in the RC-FILE

by default. A "!!Hint:" message will be printed, if any of these checks

are used.

FIPS-140
ISM
PCI
BSI TR-02102 (2016-01)
BSI TR-03116-4
RFC 2818
RFC 6125
RFC 6797
RFC 7525

BSI TR-02102-2 (+tr-02102+ tr-02102- +bsi)

Checks if connection and ciphers are compliant according TR-02102-2,

see https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Publikationen

/TechnischeRichtlinien/TR02102/BSI-TR-02102-2_pdf.pdf?__blob=publicationFile

(following headlines are taken from TR-02102-2 Version 2016-01)

3.1.3 Schlüssellängen bei EC-Verfahren

3.2 SSL/TLS_Versionen

Only TLSv1.2 allowed (except for +tr-02102- which also allows

TLSv1.1)

3.3.1 Empfohlene Cipher Suites

Allows only *DHE-*-SHA256, *DHE-*-SHA384, *DH-*-SHA256 and

*DH-*-SHA384 ciphers and PSK ciphers with ephermeral keys.

For +tr-02102+ they must be AES-GCM, +tr02102- also allows

AES-CBC.

3.3.2 Übergangsregelungen

SHA1 temporary allowed. SHA256 and SHA384 recommended.

RC4 not reocmmended.

Use of SHA1 will only be checked for +tr-02102+

3.4.1 Session Renegotation

Only server-side (secure) renegotiation allowed (see RFC5280).

3.4.2 Verkürzung der HMAC-Ausgabe

Truncated HMAC according RFC 6066 not recommended.

3.4.3 TLS-Kompression und der CRIME-Angriff

No TLS compression.

3.4.4 Der Lucky 13-Angriff
3.4.5 Die "Encrypt-thn-MAC"-Erweiterung

Use of AES-GCM ciphers only.

Use of Encrypt-then-MAC according RFC 7366 cannot be checked.

3.4.6 Die Heartbeat-Erweiterung

Target must not support the heartbeat extension.

3.4.7 Die Extended Master Secret Extension

Use of Extended Master Secret Extension according RFC 7627 cannot

be checked.

3.5 Authentisierung der Kommunikationspartner

Not checked as only applicable for VPN connections.

3.6 Domainparameter und Schlüssellängen

Check if signature key is > 2000 bits.

3.6.1 Verwendung von elliptischen Kurven

**NOT YET IMPLEMENTED**

Use only following curves according RFC 5639 and RFC 7027:

brainpoolP256r1, brainpoolP384r1, brainpoolP512r1

Use of secp256r1 and secp384r1 temporary allowed.

4.1 Schlüsselspeicherung

This requirement is not testable from remote.

4.1 Umgang mit Ephemeralschlüsseln

This requirement is not testable from remote.

4.3 Zufallszahlen

This requirement is not testable from remote.

BSI TR-03116-4 (+tr-03116+ +tr-03116- +bsi)

Checks if connection and ciphers are compliant according TR-03116-4,

see https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/Publikationen

/TechnischeRichtlinien/TR03116/BSI-TR-03116-4.pdf?__blob=publicationFile

(following headlines are taken from there)

2.1.1 TLS-Versionen und Sessions

Allows only TLS 1.2.

2.1.2 Cipher Suites

Cipher suites must be ECDHE-ECDSA or -RSA with AES128 and SHA265.

For curiosity, stronger cipher suites with AES256 and/or SHA384 are

not not allowed. To follow this curiosity the +bsi-tr-03116- (lazy)

check allows the stronger cipher suites ;-)

2.1.1 TLS-Versionen und Sessions

The TLS session lifetime must not exceed 2 days.

2.1.4.2 Encrypt-then-MAC-Extension

2.1.4.3 OCSP-Stapling

MUST have OCSP Stapling URL.

4.1.1 Zertifizierungsstellen/Vertrauensanker

Certificate must provide all root CAs. (NOT YET IMPLEMENTED).

Should use a small certificate trust chain.

4.1.2 Zertifikate

Must have CRLDistributionPoint or AuthorityInfoAccess.

End-user certificate must not be valid longer than 3 years.

Root-CA certificate must not be valid longer than 5 years.

Certificate extension pathLenConstraint must exist, and should be

a small value ("small" is not defined).

All certificates must contain the extension KeyUsage.

Wildcards for CN or Subject or SubjectAltName are not allowed

in any certificate.

EV certificates are recommended (NOT YET checked properly).

4.1.3 Zertifikatsverifikation

Must verify all certificates in the chain down to their root-CA.

(NOT YET IMPLEMENTED).

Certificate must be valid according issue and expire date.

All Checks must be doen for all certificates in the chain.

4.1.4 Domainparameter und Schlüssellängen

This requirement is not testable from remote.

4 5.2 Zufallszahlen

This requirement is not testable from remote.

RFC 2818 (+rfc2818)

Check if the FQDN is listed in the certificates subjectAltname.

RFC 6125 (+rfc6125)

Checks values CommonName, Subject and SubjectAltname of the

certificate for:

must all be valid characters for DNS
must not contain more than one wildcards
must not contain invalid wildcards
must not contain invalid IDN characters

RFC 6797 (+rfc6797)

Same as STS header +hsts .

RFC 7525 (+rfc7525)

Checks if connection and ciphers are compliant according RFC 7525.

See http://tools.ietf.org/rfc/rfc7525.txt

(following headlines are taken from there)

3.1.1. SSL/TLS Protocol Versions

SSLv2 and SSLv3 must not be supportetd.

TLSv1 should only be supported if there is no TLSv1.1 or TLSv1.2.

Either TLSv1.1 or TLSv1.2 must be supported, prefered is TLSv1.2.

3.1.2. DTLS Protocol Versions

DTLSv1 and DTLSv1.1 must not be supported.

3.1.3. Fallback to Lower Versions

(check implecitely done by 3.1.1, see above)

3.2. Strict TLS

Check if server provides Strict Transport Security.

(STARTTLS check NOT YET IMPLEMENTED).

3.3. Compression

Compression on TLS must not be supported.

3.4. TLS Session Resumption

Server must support resumtion and random session tickets.

(Randomnes of session tickets implemented YET experimental.)

Check if ticket is authenticated and encrypted NOT YET IMPLEMENTED.

3.5. TLS Renegotiation

Server must support renegotiation.

3.6. Server Name Indication

(Check for SNI support implemented experimental.)

4. Recommendations: Cipher Suites

4.1. General Guidelines
4.2. Recommended Cipher Suites

Check for recommended ciphers.

4.3. Public Key Length

DH parameter must be at least 256 bits or 2048 its with EC.

(Check currently, 4/2016, based on openssl which may not provide DH

parameters for all ciphers.)

4.5. Truncated HMAC

TLS extension "truncated hmac" must not be used.

6. Security Considerations
6.1. Host Name Validation

Given hostname must matches hostname in certificate's subject.

6.2. AES-GCM
6.3. Forward Secrecy
6.4. Diffie-Hellman Exponent Reuse

(NOT YET IMPLEMENTED).

6.5. Certificate Revocation

OCSP and CRL Distrbution Point in cetificate must be defined.

OUTPUT

All output is designed to make it easily parsable by postprocessors.

Following rules are used:

Lines for formatting or header lines start with =.
Lines for verbosity or tracing start with #.
Errors and warnings start with **, hints start with !!.
Empty lines are comments ;-)
Label texts end with a separation character; default is :.
Label and value for all checks are separated by at least one TAB character.
Texts for additional information are enclosed in << and >>.
N/A is used when no proper informations was found or provided.

Replace N/A by whatever you think is adequate: "No answer",

"Not available", "Not applicable", ...

Lines not described above, will have the form (be default):

        Label for information or check:  TABresult

For more details on these lines, please refer to RESULTS above.

When used in --legacy=full or --legacy=simple mode, the output

may contain formatting lines for better (human) readability.

Errors, Warnings, Hints

Errors, warnings and hints may be part of the output as needed. While

errors and warnings are printed immediately as they occour during the

program flow, hints are printed right after the corresponding result.

Errors and warnings start with a unique 3-digit number.

Hints print an additional explanation of a specific result. They are

are defined statically in the program code, or can be added on demand

by using the option --cfg-hint=KEY=TEXT .

Postprocessing Output

It is recommended to use the --legacy=quick option, if the output

should be postprocessed, as it omits the default separation character

(: , see above) and just uses on single tab character (0x09, \t or

TAB) to separate the label text from the text of the result. Example:

        Label of the performed checkTABresult

More examples for postprocessing the output can be found here:

https://github.com/OWASP/O-Saft/blob/master/contrib

CUSTOMIZATION

This tools can be customized as follows:

Using command line options

This is a simple way to redefine specific settings. Please see

CONFIGURATION OPTIONS below.

Using Configuration file

A configuration file can contain multiple configuration settings.

Syntax is simply KEY=VALUE. Please see CONFIGURATION FILE below.

Using resource files

A resource file can contain multiple command line options. Syntax

is the same as for command line options iteself. Each directory

may contain its own resource file. Please see RC-FILE below.

Using debugging files

These files are --nomen est omen-- used for debugging purposes.

However, they can be (mis-)used to redefine all settings too.

Please see DEBUG-FILE below.

Using user specified code

This file contains user specified program code. It can also be

(mis-)used to redefine all settings. Please see USER-FILE below.

Customization is done by redefining values in internal data structure

which are: %cfg, %data, %checks, %text, %scores .

Unless used in DEBUG-FILE or USER-FILE, there is no need to know

these internal data structures or the names of variables; the options

will set the proper values. The key names being part of the option,

are printed in output with the --trace-key option.

I.g. texts (values) of keys in %data are those used in output of the

Informations section. Texts of keys in %checks are used for output

in Performed Checks section. And texts of keys in %text are used

for additional information lines or texts (mainly beginning with =).

Configuration File vs. RC-FILE vs. DEBUG-FILE

CONFIGURATION FILE

Configuration Files must be specified with one of the --cfg_*

options. The specified file can be a valid path. Please note that

only the characters: -zA-Z_0-9,.\/()- are allowed as pathname.

Syntax in configuration file is: KEY=VALUE where KEY is any

key as used in internal data structure.

the keys in output).

RC-FILE

Resource files are searched for and used automatically.

For details see RC-FILE below.

DEBUG-FILE

Debug files are searched for and used automatically.

For details see DEBUG-FILE below.

USER-FILE

The user program file is included only if the --usr option was

used. For details see USER-FILE below.

CONFIGURATION OPTIONS

Configuration options are used to redefine texts and labels or score

settings used in output. The options are:

--cfg-cmd=CMD=LIST
--cfg-checks=KEY=TEXT
--cfg-data=KEY=TEXT
--cfg-hint=KEY=TEXT
--cfg-text=KEY=TEXT
--cfg-cipher=CIPHER=TEXT

KEY is the key used in the internal data structure, and TEXT is the

value to be set for this key. Note that unknown keys will be ignored

silently.

If KEY=TEXT is an exiting filename, all lines from that file are

read and set. For details see CONFIGURATION FILE below.

CIPHER must be a valid cipher suite name as shown with:

   o-saft.pl ciphers

NOTE that such configuration options should be used before any --help

or --help=* option, otherwise the changed setting is not visible.

CONFIGURATION FILE

Note that the file can contain KEY=TEXT pairs for any kind of the

configuration as given by the --cfg_CFG option.

For example when used with --cfg_text=FILE only values for %text

will be set, when used with #--cfg_data=FILE--cfg_data=FILE only values for %data

will be set, and so on. KEY is not used when KEY=TEXT is an existing

filename. Though, it's recommended to use a non-existing key, i.e.:

--cfg-text=my_file=some/path/to/private/file .

RC-FILE

The rc-file will be searched for in the working directory only.

The name of the rc-file is the name of the program file prefixed by a

. (dot), for example: .o-saft.pl.

A rc-file can contain any of the commands and options valid for the

tool itself. The syntax for them is the same as on command line. Each

command or option must be in a single line. Any empty or comment line

will be ignored. Comment lines start with # or =.

Note that options with arguments must be used as KEY=VALUE instead

of KEY VALUE.

Configurations options must be written like --cfg-CFG=KEY=VALUE

where CFG is any of: cmd, check, data, text and KEY is

any key from internal data structure (see above).

All commands and options given on command line will overwrite those

found in the rc-file.

DEBUG-FILE

All debugging functionality is defined in o-saft-dbx.pm, which will

be searched for using paths available in @INC variable.

Syntax in this file is Perl code. For details see DEBUG below.

USER-FILE

All user functionality is defined in o-saft-usr.pm, which will be

searched for using paths available in @INC variable.

Syntax in this file is Perl code.

All functions defined in o-saft-usr.pm are called when the option

--usr was given. The functions are defined as empty stub, any code

can be inserted as need. Please see perldoc o-saft-usr.pm to see

when and how these functions are called.

SHELL TWEAKS

Configuring the shell environment where the tool is startet, must be

done before the tools starts. It is not really a task for the tool

itself, but it can simplify your life, somehow.

There exist customizations for some commonly used shells, please see

the files in the ./contrib/ directory.

COMMANDS

The option --cfg-cmd=CMD=LIST can be used to define own commands.

When configuring own commands, CMD must not be one of the commands

listed with --help=intern and CMD must constist only of digits and

letters.

Examples in .o-saft.pl are +preload and +ciphercheck .

CIPHER NAMES

While the SSL/TLS protocol uses integer numbers to identify ciphers,

almost all tools use some kind of `human readable' texts for cipher

names.

These numbers (which are most likely written as hex values in source

code and documentations) are the only true identifier, and we have to

rely on the tools that they use the proper integers.

As such integer or hex numbers are difficult to handle by humans, we

decided to use human readable texts. Unfortunately no common standard

exists how to construct the names and map them to the correct number.

Some, but by far not all, oddities are described in Name Rodeo.

The rules for specifying cipher names are:

1. textual names as defined by IANA (see [IANA])
2. mapping of names and numbers as defined by IANA (see [IANA])
3. - and _ are treated the same
4. abbreviations are allowed, as long as they are unique
5. beside IANA, openssl's cipher names are preferred
6. name variants are supported, as long as they are unique
7. hex numbers can be used

[IANA] http://www.iana.org/assignments/tls-parameters/tls-parameters.txt September 2013

[openssl] ... openssl 1.0.1

If in any doubt, use +list to get an idea about the mapping.

Use --help=regex to see which regex are used to handle all these

variants herein.

Mind the traps and dragons with cipher names and what number they are

actually mapped to. In particular when --lib, --exe or --openssl

options are in use. Always use these options with +list command too.

Name Rodeo

As said above, the SSL/TLS protocol uses integer numbers to identify

ciphers, but almost all tools use some kind of human readable texts

for cipher names.

For example the cipher commonly known as DES-CBC3-SHA is identified

by 0x020701c0 (in openssl) and has SSL2_DES_192_EDE3_CBC_WITH_SHA

as constant name. A definition is missing in IANA, but there is

TLS_RSA_WITH_3DES_EDE_CBC_SHA . Thers is also 0x000A for the same

cipher DES-CBC3-SHA. Both are valid, first one when used with SSLv2,

and second one when used with SSLv3.

It's the responsibility of each tool to map the human readable cipher

name to the correct (hex, integer) identifier.

For example Firefox uses dhe_dss_des_ede3_sha, which is what?

Furthermore, there are different acronyms for the same thing in use.

For example DHE and EDH both mean "Ephemeral Diffie-Hellman".

Comments in the openssl(1) sources mention this. And for curiosity

these sources use both in cypher names but allow EDH as shortcut

only in openssl's "ciphers" command. Wonder about (up to 1.0.1h):

   openssl ciphers -V EDH
   openssl ciphers -V DHE
   openssl ciphers -V EECDH
   openssl ciphers -V ECDHE

Next example is ADH which is also known as DH_anon or DHAnon

or DHA or ANON_DH.

You think this is enough? Then have a look how many acronyms are used

for "Tripple DES".

Compared to above, the interchangeable use of - vs. _ in human

readable cipher names is just a very simple one. However, see openssl

again what following means (returns):

   openssl ciphers -v RC4-MD5
   openssl ciphers -v RC4+MD5
   openssl ciphers -v RC4:-MD5
   openssl ciphers -v RC4:!MD5
   openssl ciphers -v RC4!MD5

Looking at all these oddities, it would be nice to have a common unique

naming scheme for cipher names. We have not. As the SSL/TLS protocol

just uses a number, it would be natural to use the number as uniq key

for all cipher names, at least as key in our internal sources.

Unfortunately, the assignment of ciphers to numbers changed over the

years, which means that the same number refers to a different cipher

depending on the standard, and/or tool, or version of a tool you use.

As a result, we cannot use human readable cipher names as identifier

(aka unique key), as there are to many aliases for the same cipher.

And also the number cannot be used as unique key, as a key may have

multiple ciphers assigned.

KNOWN PROBLEMS

This section describes knwon problems, and known error messages which

may occour when using o-saft.pl. This sections can be used as FAQ too

as it gives hints and workarounds.

Segmentation fault

Sometimes the program terminates with a Segmentation fault. This

mainly happens if the target does not return certificate information.

If so, the --no-cert option may help.

**WARNING: empty result from openssl; ignored at ...

This most likely occurs when the provided cipher is not accepted by

the server, or the server expects client certificates.

**WARNING: unknown result from openssl; ignored at ...

This most likely occurs when the openssl executable is used with a

very slow connection. Typically the reason is a connection timeout.

Try to use --timeout=SEC option.

To get more information, use --v --v and/or --trace also.

**WARNING: undefined cipher description

May occour if ciphers are checked, but no description is available for

them herein. This results in printed cipher checks like:

        EXP-KRB5-RC4-MD5                no       <undef>>

instead of:

        EXP-KRB5-RC4-MD5                no       weak

**WARNING: Can't make a connection to your.tld:443; no initial data

**WARNING: Can't make a connection to your.tld:443; target ignored

This message occours if the underlaying SSL library (i.e. libssl.a)

was not able to connect to the target. Known observed reasons are:

target does not support SSL protocol on specified port
target expects a client certificate in ClientHello message

More details why the connection failed can be seen using --trace=2 .

If the targets supports SSL, it should be at least possible to check

for supported ciphers using +cipherall instead of +cipher .

Use of uninitialized value $headers in split ... do_httpx2.al)

The warning message (like follows or similar):

Use of uninitialized value $headers in split at blib/lib/Net/SSLeay.pm

(autosplit into blib/lib/auto/Net/SSLeay/do_httpx2.al) line 1290.

occurs if the target refused a connection on port 80.

This is considered a bug in Net::SSLeay.

Workaround to get rid of this message: use --no-http option.

invalid SSL_version specified at ... IO/Socket/SSL.pm

This error may occur on systems where a specific SSL version is not

supported. Subject are mainly SSLv2, SSLv3 TLSv1.3 and DTLSv1.

For DTLSv1 the full message looks like:

      invalid SSL_version specified at C:/programs/perl/perl/vendor/lib/IO/Socket/SSL.

Use of uninitialized value $_[0] in length at (eval 4) line 1.

This warning occours with IO::Socket::SSL 1.967, reason is unknown.

It seems not to harm functionality, hence no workaround, just ignore.

Use of uninitialized value in subroutine entry at lib/IO/Socket/SSL.pm line 430.

Some versions of IO::Socket::SSL return this error message if *-MD5

ciphers are used with other protocols than SSLv2.

Workaround: use --no-md5-cipher option.

Can't locate auto/Net/SSLeay/CTX_v2_new.al in @INC ...

Underlaying library doesn't support the required SSL version.

Read error: Connection reset by peer (,199725) at blib/lib/Net/SSLeay.pm (autosplit into blib/lib/auto/Net/SSLeay/tcp_read_all.al) line 535.

Error reported by some Net::SSLeay versions. Reason may be a timeout.

This error cannot be omitted or handled properly.

Workaround: try to use same call again (no guarantee, unfortunatelly)

Odd number of elements in anonymous hash at Net/SSLinfo.pm line 1613.

This warning from perl have been observed when the connection to the

target to check for supported ciphers cannot be established.

This message can be ignored.

openssl: ...some/path.../libssl.so.1.0.0: no version information available (required by openssl)

Mismatch of openssl executable and loaded underlaying library. This

most likely happens when options --lib=PATH and/or --exe=PATH are

used. See also Note on SSL versions .

Hint: use following commands to get information about used libraries:

  o-saft.pl +version
  o-saft.pl --v --v +version

Integer overflow in hexadecimal number at ...

This error message may occour on 32-bit systems if perl was not com-

piled with proper options. I.g. perl automatically converts the value

to a floating pont number.

Please report a bug with output of following command:

  o-saft.pl +s_client +dump your.tld

<<openssl did not return DH Paramter>>

Text may be part of a value. This means that all checks according DH

parameters and logkam attack cannot be done.

Workaround: try to use --openssl=TOOL option.

This text may appears in any of the compliance checks (like +rfc7525)

which may be a false positive. For these checks openssl is also used

to get the DH Parameter.

Workaround: not available yet

No output with +help and/or --help=todo

On some (mainly Windows-based) systems using

  o-saft.pl +help
  o-saft.pl --help

does not print anything.

Workaround: use --v option.

  o-saft.pl +help --v

or

  o-saft.pl +help | more

Character set (like UTF-8) not recognized in some tools

Some tools do not diplay all characters properly, i.e. some versions

of podviewer. It is not the obligation of this tool to fix well known

bugs in other tools. However, we can offer workarounds.

Workaround: generate the affected output using --std-format=* options

For example:

   o-saft.pl --no-rc --std-format=raw --help=gen-pod

**WARNING: on MSWin32 additional option --v required, sometimes ...

On some (mainly Windows-based) systems this may happen when calling

for example:

  o-saft.pl --help=FAQ

which then may produce:

  **WARNING: on MSWin32 additional option  --v  required, sometimes ...
  === reading: ./.o-saft.pl (RC-FILE done) ===
  === reading: Net/SSLinfo.pm (O-Saft module done) ===
  **USAGE: no command given
  # most common usage: 
    o-saft.pl +info   your.tld
    o-saft.pl +check  your.tld
    o-saft.pl +cipher your.tld
  # for more help use:
    o-saft.pl --help

Workaround: use full path to perl.exe, for example

  C:\Programs\perl\bin\perl.exe o-saft.pl --help=FAQ

Performance Problems

There are various reasons when the program responds slow, or seems to

hang. Performance issues are most likely a target-side problem. Most

common reasons are (no specific order):

a) DNS resolver problems

Try with --no-dns

b) target does not accept connections for https

Try with --no-http

c) target's certificate is not valid

Try with --no-cert

d) target expects that the client provides a client certificate

No option provided yet ...

e) target does not handle Server Name Indication (SNI)

Try with --no-sni

f) use of external openssl(1) executable

Use --no-openssl

g) target does not respond at all and/or blocks

Use --ssl-error

For a detailed description, please see Connection Problems.

Other options which may help to get closer to the problem's cause:

--trace-time, --timeout=SEC, --trace, --trace-cmd

Using --trace=time should show following times:

DNS: 1 - 10 sec
no SNI: 1 - 10 sec
connection test: 1 - 5 sec
need_default: <5 sec
need_cipher: 1 - 60 sec (+cipher with socket)
need_cipher: 1 - 20 sec (+cipherraw)
prepare checks: 2 - 20 sec
info: <1 sec
check: <1 sec

LIMITATIONS

Commands

Some commands cannot be used together with others, for example:

+cipher, +ciphers, +list, +libversion, +version, +check, +help,

+protocols .

+quick should not be used together with other commands, it returns

strange output then.

+protocols requires openssl(1) with support for -nextprotoneg

option. Otherwise the value will be empty.

Options

The option --port=PORT must preceed --host=HOST for a target like

HOST:PORT .

The characters + and = cannot be used for --separator==CHAR option.

Following strings should not be used in any value for options:

+check, +info, +quick, --header

as they my trigger the ---header option unintentional.

The used timeout(1) command cannot be defined with a full path like

openssl(1) can with the --openssl=path/to/openssl.

--cfg_text=FILE cannot be used to redefine the texts yes and no

as used in the output for +cipher command.

Checks (general)

+constraints

This check is only done for the certificate provided by the target.

All other certificate in the chain are not checked.

This is currently (2018) a limitation in o-saft.pl.

Broken pipe

This error message most likely means that the connection to specified

target was not possible (firewall or whatever reason).

Target Certificate Chain Verification

The systems default capabilities i.e. libssl.so, openssl, are used to

verify the target's certificate chain. Unfortunately various systems

have implemented different approaches and rules how identify and how

to report a successful verification. As a consequence this tool can

only return the same information about the chain verification as the

used underlying tools. If that information is trustworthy depends on

how trustworthy the tools are.

These limitations apply to following commands:

+verify
+selfsigned

Following commands and options are useful to get more information:

+chain_verify, +verify, +error_verify, +chain, +s_client
--ca-file, --ca-path, --ca-depth

User Provided Files

Please note that there cannot be any guarantee that the code provided

in the DEBUG-FILE o-saft-usr.pm or USER-FILE o-saft-usr.pm

will work flawless. Obviously this is the user's responsibility.

Problems and Errors

Checking the target for supported ciphers may return that a cipher is

not supported by the server misleadingly. Reason is most likely an

improper timeout for the connection. See --timeout=SEC option.

If the specified targets accepts connections but does not speak SSL,

the connection will be closed after the system's TCP/IP-timeout. This

script will hang (about 2-3 minutes).

If reverse DNS lookup fails, an error message is returned as hostname,

like: <<gethostbyaddr() failed>>.

Workaround to get rid of this message: use --no-dns option.

All checks for EV are solely based on the information provided by the

certificate.

Some versions of openssl (< 1.x) may not support all required options

which results in various error messages or --more worse-- may not be

visibale at all. Available functionalitity of openssl will be checked

for right at the beginning Proper Warnings and hints are printed.

Following table shows the openssl option and how to disbale it within

o-saft:

-nextprotoneg --no-nextprotoneg
-reconnect --no-reconnect
-tlsextdebug --no-tlsextdebug
-alpn --no-alpn

Connection Problems

Sometimes the connection cannot be established. This may have various

reasons. Unfortunaly this script seems to hang then. In particular

when checking for ciphers with +cipher or +cipherall . The reason

is most likely that the server does not respond to the TCP/IP request

and hence the script closes the connection after the configured time-

out (see --timeout=SEC option).

Continous connection attempts can be inhibited with the --ssl-error

option, which is set by default. Avoiding further connections results

in a loss of information and consequentely leading to wrong checks.

It is a trade-off to wait for all information done accurately, or to

get the results quickly. The logic to stop connecting for --ssl-error

can be controlled with following additional options:

--ssl-error-max=CNT - max. continous errors
--ssl-error-timeout=SEC - timeout when to treat a failure as error
--ssl-error-total=CNT - max. amount of errors

This means that no more connections are made when more than

--ssl-error-max errors occour sequentialy

or

--ssl-error-total errors occoured

Examples:

--ssl-error-max=3
--ssl-error-timeout=6
--ssl-error-total=6

no more connections are made if for example any sequence of timeouts

occour:

 0 5 2 2                   - --ssl-error-max matches 
 0 1 3 0 0 0 4 1 2 2 2     - --ssl-error-max matches
 0 5 0 2 0 2 2 0 2 0 2     - --ssl-error-total matches

This allows to fine-tune the condition when to stop connecting to the

target. For example, continous but not consecutive timeouts may indi-

cate a bad or instable network connection, but not that the target to

be connected blocks. In such a case sequence of timeouts like follows

may be observed (assuming --ssl-error-max=3):

 0 5 1 2 2 2 4 2 3 2 3 3 3 2
       ^                 ^____ stop for --ssl-error-timeout=3
       |______________________ stop for --ssl-error-timeout=2

On normal (even slow) network connections dozens of connections per

second are usual, hence the timeout is always 0 or 1. Based on that

experience --ssl-error is enabled and set with defaults as follows:

--ssl-error-max=5
--ssl-error-timeout=1
--ssl-error-total=10

Poor Systems

Use of openssl(1) is disabled by default on Windows due to various

performance problems. It needs to be enabled with --openssl option.

On Windows the usage of openssl s_client needs to be enabled using

--s_client option.

On Windows it's a pain to specify the path for --openssl=TOOL option.

Variants are:

--openssl=/path/to/openssl.exe
--openssl=X:/path/to/openssl.exe
--openssl=\path\to\openssl.exe
--openssl=X:\path\to\openssl.exe
--openssl=\\path\\to\\openssl.exe
--openssl=X:\\path\\to\\openssl.exe

You have to fiddle around to find the proper one.

Debug and Trace Output

When both --trace-key and --trace-cmd options are used, output is

mixed, obviously. Hint: output for --trace-cmd always contains "CMD".

Any --trace* option implies --trace-time .

DEPENDENCIES

All Perl modules and all private moduels and files will be searched

for using paths available in the @INC variable. @INC will

be prepended by following paths:

.
./lib
INSTALL_PATH
INSTALL_PATH/lib

Where INSTALL_PATH is the path where the tool is installed.

To see which files have been included use:

   o-saft.pl +version --v --user

Perl Modules

IO::Socket::SSL(3pm)
IO::Socket::INET(3pm)
Net::SSLeay(3pm)
Net::SSLinfo
Net::SSLhello

Perl modules loaded and used for some options only:

Net::DNS(3pm)
Time::Local(3pm)

Additional Files used if requested

.o-saft.pl
o-saft-dbx.pm
o-saft-man.pm
o-saft-usr.pm
o-saft-README
o-saft-docker

INSTALLATION

The tool can be installed in any path. It just requres the modules as

described in DEPENDENCIES above. However, it's recommended that the

modules Net::SSLhello and Net::SSLinfo are found in the directory

./Net/ where o-saft.pl is installed.

For security reasons, most modern libraries disabled or even removed

insecure or "dirty" functionality. As this tool's purpose is to find

such insecure settings, functions, etc., it needs these dirty things

enabled. What we need is (incomplete list):

insecure protocols like SSLv2, SSLv3
more more ciphers enabled, like NULL-MD5, AECDH-NULL-SHA, etc.
some SSL extensions and options

Therefore we recommend to compile and install at least following:

openssl with SSLv2, SSLv3 and more ciphers enabled
Net::SSLeay compiled with openssl version as described before.

Please read the SECURITY section first before following the install

instructions below.

OpenSSL

Currently (since 18.06.18) it is recommend to build openssl using

   contrib/install_openssl.sh

Other possibilities are:

compiling openssl using following sources

https://github.com/PeterMosmans/openssl/

see Example: Compile OpenSSL,

use any of the precomiled versions provided by https://testssl.sh/

The sources are available at

https://github.com/PeterMosmans/openssl/archive/1.0.2-chacha.zip

A precomiled static versions are available at

https://github.com/drwetter/testssl.sh/tree/master/bin

For all following installation examples we assume:

openssl-1.0.2-chacha.zip or openssl-1.0.2d.tar.gz
/usr/local as bae installation directory
a bourne shell (sh) compatible shell

Example: Precompiled OpenSSL

Simply download the tarball or zip file for your platform, unpack it,

and install (copy) the binaries into a directory of your choice.

Example: Compile OpenSSL

OpenSSL can be used from http://openssl.org/ or, as recommended, from

https://github.com/PeterMosmans/openssl/ .

OpenSSL-chacha

Compiling and installing the later is as simple as:

   unzip openssl-1.0.2-chacha.zip
   cd openssl-1.0.2-chacha
   ./config --shared -Wl,-rpath=/usr/local/lib
   make
   make test
   make install

which will install openssl, libssl.so, libcrypto.so and some include

files as well as the include files in /usr/local/ .

The shared version of the libraries are necessary for Net::SSLeay.

OpenSSL.org

Building openssl from the offical openssl.org sources requires some

patching before compiling and installing the libraries and binaries.

Example with openssl-1.0.2d:

  echo == unpack tarball
  tar xf openssl-1.0.2d.tar.gz
  cd openssl-1.0.2d

  echo == backup files to be modified
  cp ssl/s2_lib.c{,.bak}
  cp ssl/s3_lib.c{,.bak}
  cp ssl/ssl3.h{,.bak}
  cp ssl/tls1.h{,.bak}

  echo == patch files
  vi ssl/tls1.h         +/TLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES/
           # define TLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES  1
  vi ssl/ssl3.h ssl/s{2,3}_lib.c   +"/# *if 0/"
           #==> remove all   # if 0  and corresponding  #endif
           #    except if lines contain:
           #        _FZA
           #        /* Fortezza ciphersuite from SSL 3.0
           #        /* Do not set the compare functions,
           #        if (s->shutdown & SSL_SEND_SHUTDOWN)

  echo == configure with static libraries
  echo omitt the zlib options if zlib-1g-dev is not installed
  echo omitt the krb5 options if no kerberos libraries available
  ./config --prefix=/usr/local --openssldir=/usr/local/ssl \
      enable-zlib zlib zlib-dynamic enable-ssl2 \
      enable-krb5 --with-krb5-flavor=MIT \
      enable-mdc2 enable-md2  enable-rc5  enable-rc2 \
      enable-cms  enable-ec   enable-ec2m enable-ecdh enable-ecdsa \
      enable-gost enable-seed enable-idea enable-camellia \
      enable-rfc3779 enable-ec_nistp_64_gcc_128 \
      experimental-jpake -fPIC \
      -DTEMP_GOST_TLS -DTLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES \
      shared

  echo == make binaries and libraries
  make depend
  make
  make test
  make install

  echo == if you want static binaries and libraries
  make clean
  echo same ./config as before but without shared option
  ./config --prefix=/usr/local --openssldir=/usr/local/ssl \
      enable-zlib zlib zlib-dynamic enable-ssl2 \
      enable-krb5 --with-krb5-flavor=MIT \
      enable-mdc2 enable-md2 enable-rc5 enable-rc2 \
      enable-cms  enable-ec   enable-ec2m enable-ecdh enable-ecdsa \
      enable-gost enable-seed enable-idea enable-camellia \
      enable-rfc3779 enable-ec_nistp_64_gcc_128 \
      experimental-jpake -fPIC \
      -DTEMP_GOST_TLS -DTLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES
  make depend
  make
  make test
  echo next make will overwrite the previously installed dynamic
  echo shared openssl binary with the static openssl binary
  make install

Example: Compile Net::SSLeay

To enable support for ancient protocol versions, Net::SSLeay must be

compiled manually after patching 'SSLeay.xs' (see below).

Reason is, that Net::SSLeay enables some functionality for SSL/TLS

according the identified openssl version. There is, currently (2015),

no possibility to enable this functionality by passing options on to

the configuration script perl Makefile.PL.

   echo == unpack tarball
   tar xf Net-SSLeay-1.72.tar.gz
   cd Net-SSLeay-1.72

   echo == patch files
   echo "edit SSLeay.xs and change some #if as described below"
   env OPENSSL_PREFIX=/usr/local perl Makefile.PL PREFIX=/usr/local \
         INC=/usr/local/include  DEFINE=-DOPENSSL_BUILD_UNSAFE=1
   make
   make install
   cd /tmp && o-saft.pl +version

SSLeay.xs needs to be changed as follows:

search for

   #ifndef OPENSSL_NO_SSL2
   #if OPENSSL_VERSION_NUMBER < 0x10000000L
 
   const SSL_METHOD *
   SSLv2_method()
 
   #endif
   #endif
 
   #ifndef OPENSSL_NO_SSL3
   #if OPENSSL_VERSION_NUMBER < 0x10002000L

   const SSL_METHOD *
   SSLv3_method()

   #endif
   #endif

and replace by

   const SSL_METHOD *
   SSLv2_method()

   const SSL_METHOD *
   SSLv3_method()

Note that Net::SSLeay will be installed in /usr/local/ then. This

can be adapted to your needs by passing another path to the PREFIX

and DESTDIR parameter.

Following command can be used to check which methods are avilable in

Net::SSLeay, hence above patches can be verified:

    perl -MLNet::SSLinfo -le print Net::SSLinfo::ssleay_test();

Testing OpenSSL

After installation as descibed above finished, openssl may be tested:

   echo already installed openssl (found with PATH environment)
   openssl ciphers -v
   openssl ciphers -V -ssl2
   openssl ciphers -V -ssl3
   openssl ciphers -V ALL
   openssl ciphers -V ALL:COMPLEMENTOFALL
   openssl ciphers -V ALL:eNULL:EXP

   echo own compiled and installed openssl 
   /usr/local/openssl ciphers -v
   /usr/local/openssl ciphers -V -ssl2
   /usr/local/openssl ciphers -V -ssl3
   /usr/local/openssl ciphers -V ALL
   /usr/local/openssl ciphers -V ALL:COMPLEMENTOFALL
   /usr/local/openssl ciphers -V ALL:eNULL:EXP

The difference should be obvious. Note, the commands using ALL:COMPLEMENTOFALL and ALL:eNULL:EXP should return the same result.

Testing Net::SSLeay

As we want to test the separately installed Net::SSLeay, it is best

to do it with o-saft.pl itself:

   o-saft.pl +version

we should see a line similar to follwong at the end of the output:

   Net::SSLeay   1.72  /usr/local/lib/x86_64-linux-gnu/perl/5.20.2/Net/SSLeay.pm

Now check for supported (known) ciphers:

   o-saft.pl ciphers -V

we should see lines similar to those of the last /usr/local/openssl

call. However, it should contain more cipher lines.

Stand-alone Executable

Some people asked for a stand-alone executable (mainly for Windows).

Even Perl is a scripting language there are situations where a stand-

alone executable would be nice, for example if the installed perl and

its libraries are outdated, or if perl is missing at all.

Currently (2016) there are following possibilities to generate such a

stand-alone executable:

perl with PAR::Packer module

     pp -C -c o-saft.pl
     pp -C -c o-saft.pl -M Net::DNS -M Net::SSLeay -M IO::Socket \
                        -M Net::SSLinfo -M Net::SSLhello -M osaft
     pp -C -c checkAllCiphers.pl
     pp -C -c checkAllCiphers.pl -M Net::DNS

ActiveState perl with its perlapp

     perlapp --clean o-saft.pl
     perlapp --clean o-saft.pl -M Net::DNS -M Net::SSLeay -M IO::Socket \
                 -M Net::SSLinfo -M Net::SSLhello -M osaft
     perlapp --clean checkAllCiphers.pl
     perlapp --clean checkAllCiphers.pl -M Net::DNS -M osaft

perl2exe from IndigoSTar

     perl2exe o-saft.pl
     perl2exe checkAllCiphers.pl

For details on building the executable, for example how to include

all required modules, please refer to the documentation of the tool.

Note that pre-build executables (build by perlapp, perl2exe) cannot

be provided due to licence problems.

Also note that using stand-alone executable have not been tested the

same way as the o-saft.pl itself. Use them at your own risk.

DOCKER

The tool can be used inside a Docker image. With o-saft-docker and a

Dockerfile (both are part of the distribution), a proper Docker image

will be build easily. o-saft-docker can also be used to run commands

with o-saft.pl inside the Docker image, example:

  o-saft-docker +info some.tld

For more details, please refer to:

  o-saft-docker -help
  o-saft-docker usage

HACKER's INFO

Note on SSL versions

Automatically detecting the supported SSL versions of the underlaying

system is a hard job and not always possible. Reasons could be:

used Perl modules (Socket::SSL, Net::SSLeay) does not handle errors

properly. Erros may be:

  invalid SSL_version specified at ... IO/Socket/SSL.pm

  Use of uninitialized value in subroutine entry at lib/IO/Socket/SSL.pm

the underlaying libssl does not support the version, which then may

result in segmentation fault

the underlaying libssl is newer than the Perl module and the module

has not been reinstalled. This most often happens with Net::SSLeay

This can be detected with (see version numbers for Net::SSLeay):

   o-saft.pl +version

perl (in particular a used module, see above) may bail out with a

compile error, like

   Can't locate auto/Net/SSLeay/CTX_v2_new.al in @INC ...

We try to detect unsupported versions and disable them automatically,

a warning like follwoing is shown then:

   **WARNING: SSL version SSLv2 not supported by openssl

If problems occour with SSL versions, following commands and options

may help to to get closer to the reason or can be used as workaround:

   o-saft.pl +version
   o-saft.pl +version | grep versions
   o-saft.pl +version | grep 0x
   o-saft.pl +protocols your.tld
   o-saft.pl +protocols your.tld --no-rc

If problems occour with SSL versions, following commands and options

Checking for SSL version is done at one place in the code, search for

    supported SSL versions

Using private libssl.so and libcrypt.so

For all cryptographic functionality the libraries installed on the

system will be used. This is in particular Perl's Net:SSLeay module,

the system's libssl.so and libcrypt.so and the openssl executable.

It is possible to provide your own libraries, if the P module and

the executable are linked using dynamic shared objects (aka shared

library, position independent code).

The appropriate option is --lib=PATH .

On most systems these libraries are loaded at startup of the program.

The runtime loader uses a preconfigured list of directories where to

find these libraries. Also most systems provide a special environment

variable to specify additional paths to directories where to search

for libraries, for example the LD_LIBRARY_ variable.

This is the default environment variable used herein. If your system

uses another name it must be specified with the --envlibvar=NAME

option, where NAME is the name of the environment variable.

Understanding --exe=PATH, --lib=PATH, --openssl=FILE

If any of --exe=PATH or --lib=PATH is provided, the pragram calls

(exec) itself recursively with all given options, except the option

itself. The environment variables LD_LIBRARY_PATH and PATH are

set before executing as follows:

prepend PATH with all values given with --exe=PATH
prepend LD_LIBRARY_PATH with all values given with --lib=PATH

This is exactly, what Cumbersome Approach below describes. So these

option simply provide a shortcut for that.

Note that --openssl=TOOL is a full path to the openssl executable

and will not be changed. However, if it is a relative path, it might

be searched for using the previously set PATH (see above).

Note that LD_LIBRARY_PATH is the default. It can be changed with

the --envlibvar=NAME option.

While --exe mainly impacts the openssl executable, --lib also

impacts o-saft.pl itself, as it loads other shared libraries if found.

Bear in mind that all these options can affect the behaviour of the

openssl subsystem, influencing both which executable is called and

which shared libraries will be used.

NOTE that no checks are done if the options are set proper. To verify

the settings, following commands may be used:

   o-saft.pl --lib=YOU-PATH --exe=YOUE-EXE +version
   o-saft.pl --lib=YOU-PATH --exe=YOUE-EXE --v +version
   o-saft.pl --lib=YOU-PATH --exe=YOUE-EXE --v --v +version

Why so many options? Exactly as described above, these options allow

the users to tune the behaviour of the tool to their needs. A common

use case is to enable the use of a separate openssl build independent

of the openssl package used by the operating system. This allows the

user fine grained control over openssl's encryption suites which are

compiled/available, without affecting the core system.

Caveats

Depending on your system and the used modules and executables, it can

be tricky to replace the configured shared libraries with own ones.

Reasons are:

a) the linked library name contains a version number,

b) the linked library uses a fixed path,

c) the linked library is searched at a predefined path,

d) the executable checks the library version when loaded.

Only the first one a) can be circumvented. The last one d) can often

be ignored as it only prints a warning or error message.

To circumvent the "name with version number" problem try following:

1. use ldd (or a similar tool) to get the names used by openssl:

ldd /usr/bin/openssl

which returns something like:

libssl.so.0.9.8 => /lib/libssl.so.0.9.8 (0x00007f940cb6d000)

libcrypto.so.0.9.8 => /lib/libcrypto.so.0.9.8 (0x00007f940c7de000)

libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f940c5d9000)

libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f940c3c1000)

libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f940c02c000)

/lib64/ld-linux-x86-64.so.2 (0x00007f940cdea000)

Here only the first two libraries are important. Both, libcrypto.so

and libssl.so need to be version "0.9.8" (in this example).

2. create a directory for your libraries, i.e.:

mkdir /tmp/dada

3. place your libraries there, assuming they are:

/tmp/dada/libssl.so.1.42

/tmp/dada/libcrypto.so.1.42

4. create symbolic links in that directory:

ln -s libssl.so.1.42 libssl.so.0.9.8

ln -s libcrypto.so.1.42 libcrypto.so.0.9.8

5. test program with following option:

   o-saft.pl +libversion --lib=/tmp/dada
   o-saft.pl +list --v   --lib=/tmp/dada

or:

   o-saft.pl +libversion --lib=/tmp/dada -exe=/path/to-openssl
   o-saft.pl +list --v   --lib=/tmp/dada -exe=/path/to-openssl

6. start program with your options, i.e.:

   o-saft.pl --lib=/tmp/dada +ciphers

This works if openssl(1) uses the same shared libraries as

Net:SSLeay(3pm), which most likely is the case.

It's tested with Unix/Linux only. It may work on other platforms also

if they support such an environment variable and the installed

Net::SSLeay(3pm) and openssl(1) are linked using dynamic shared

objects.

Depending on compile time settings and/or the location of the used

tool or lib, a warning like following may occur:

  WARNING: can't open config file: /path/to/openssl/ssl/openssl.cnf

This warning can be ignored, usually as req or ca sub commands of

openssl is not used here.

To fix the problem, either use --openssl-cnf=FILE option or set the

the environment variable OPENSSL_CONF properly.

Cumbersome Approach

A more cumbersome approach to call this program is to set following

environment variables in your shell:

  PATH=/tmp/dada-1.42/apps:$PATH
  LD_LIBRARY_PATH=/tmp/dada-1.42

Windows Caveats

I.g. the used libraries on Windows are libeay32.dll and ssleay32.dll.

Windows also supports the LD_LIBRARY_PATH environment variable. If it

does not work as expected with that variable, it might be possible to

place the libs in the same directory as the corresponding executable

(which is found by the PATH environment variable).

Using CGI mode

This script can be used as CGI application. Output is the same as in

common CLI mode, using 'Content-Type:text/plain'. Keep in mind that

the used modules like Net::SSLeay will write some debug messages

on STDERR instead STDOUT. Therefore multiple --v and/or --trace

options behave slightly different.

No additional external files like RC-FILE or DEBUG-FILE are read

in CGI mode; they are silently ignored.

Some options are disabled in CGI mode because they are dangerous or

don't make any sense.

WARNING

There are no input data validation checks implemented herein. All

input data is url-decoded once and then used verbatim.

More advanced checks must be done outside before calling this tool.

It's not recommended to run this tool in CGI mode.

You have been warned!

Using user specified code

There are some functions called within the program flow, which can be

filled with any Perl code. Empty stubs of the functions are prepared

in o-saft-usr.pm. See also USER-FILE.

DEBUG

Debugging, Tracing

Following options and commands are useful for hunting problems with

SSL connections and/or this tool. Note that some options can be given

multiple times to increase amount of listed information. Also keep in

mind that it's best to specify --v as very first argument.

Note that the file o-saft-dbx.pm is required, if any --trace*

or --v option is used.

Commands

+dump
+libversion
+s_client
+todo
+version

Options

--v
--v--
--trace
--trace-arg
--trace-cmd
--trace-key

Empty or undefined strings are written as <<undefined>> in texts.

Some parameters, in particular those of HTTP responses, are written

as <<response>>. Long parameter lists are abbreviated with ....

Output

When using --v and/or --trace options, additional output will

be prefixed with a # (mainly as first, left-most character.

Following formats are used:

#[space]

Addition text for verbosity (--v options).

#[variable name][TAB]

Internal variable name (--trace-key options).

#o-saft.pl::
#Net::SSLinfo::

Trace information for --trace options.

#{

Trace information from NET::SSLinfo for --trace options.

These are data lines in the format: #{ variable name : value #}

Note that value here can span multiple lines and ends with #}

Using outdated modules

The tools was designed to work with old Perl modules too. When using

old modules, a proper **WARNING: will be printed. These warinings

cannot be switched of using --no-warning .

The warning also informs about the missing functionality or check.

I.g. it is best to install newer versions of the module if possible.

A good practice to check if modules are available in a proper version

is to call:

 o-saft.pl +version
 o-saft.pl +version --v --v

Following example shows the result without warnings:

     === reading: ./.o-saft.pl (RC-FILE done) ===
     === reading: Net/SSLhello.pm (O-Saft module done) ===
     === reading: Net/SSLinfo.pm (O-Saft module done) ===
     === ./o-saft.pl 16.09.09 ===
         Net::SSLeay::
            ::OPENSSL_VERSION_NUMBER()    0x268443744
            ::SSLeay()                    0x268443744
         Net::SSLeay::SSLeay_version()    OpenSSL 1.0.2-chacha (1.0.2f-dev)
     = openssl =
         version of external executable   OpenSSL 1.0.2-chacha (1.0.2f-dev)
         external executable              /opt/openssl-chacha/bin/openssl
         used environment variable (name) LD_LIBRARY_PATH
         environment variable (content)   <<undef>>
         path to shared libraries         
         full path to openssl.cnf file    <<undef>>
         common openssl.cnf files         /usr/lib/ssl/openssl.cnf \
                                          /etc/ssl/openssl.cnf \
                                          /System//Library/OpenSSL/openssl.cnf \
                                          /usr/ssl/openssl.cnf
         URL where to find CRL file       <<undef>>
         directory with PEM files for CAs /opt/tools/openssl-chacha/ssl/certs
         PEM format file with CAs         /etc/ssl/certs/ca-certificates.crt
         common paths to PEM files for CAs /etc/ssl/certs /usr/lib/certs \
                                           /System/Library/OpenSSL
         common PEM filenames for CAs     ca-certificates.crt \
                                          certificates.crt certs.pem
         number of supported ciphers      177
         openssl supported SSL versions   SSLv3 TLSv1 TLSv11 TLSv12
         o-saft.pl known SSL versions     SSLv2 SSLv3 TLSv1 TLSv11 TLSv12 TLSv13 \
                                          DTLSv09 DTLSv1 DTLSv11 DTLSv12 DTLSv13
     = o-saft.pl +cipherall =
         default list of ciphers          0x03000000 .. 0x030000FF, 0x0300C000 .. 0x0300C0FF, \
                                          0x0300CC00 .. 0x0300CCFF, 0x0300FE00 .. 0x0300FFFF,
                                          
     = Required (and used) Modules =
         @INC                 ./ ./lib . /bin /usr/share/perl5 \
                              /usr/lib/x86_64-linux-gnu/perl5/5.20 \
                              /usr/lib/x86_64-linux-gnu/perl/5.20 \
                              /usr/share/perl/5.20 /usr/local/lib/site_perl .
     =   module name            VERSION  found in
     =   ----------------------+--------+------------------------------------------
         IO::Socket::INET       1.35     /usr/lib/x86_64-linux-gnu/perl/5.20/IO/Socket/INET.pm
         IO::Socket::SSL        2.002    /usr/share/perl5/IO/Socket/SSL.pm
         Net::DNS               0.81     /usr/lib/x86_64-linux-gnu/perl5/5.20/Net/DNS.pm
         Net::SSLeay            1.72     /usr/lib/x86_64-linux-gnu/perl5/5.20/Net/SSLeay.pm
         Net::SSLinfo           16.06.01 Net/SSLinfo.pm
         Net::SSLhello          16.05.16 Net/SSLhello.pm
         osaft                  16.05.10 osaft.pm

Following example shows the result with warnings:

     === reading: ./.o-saft.pl (RC-FILE done) ===
     === reading: ./Net/SSLhello.pm (O-Saft module done) ===
     **WARNING: ancient Net::SSLeay 1.35 < 1.49; cannot use ::initialize at /Net/SSLinfo.pm line 481.
     === reading: ./Net/SSLinfo.pm (O-Saft module done) ===
     **WARNING: ancient perl has no 'version' module; version checks may not be accurate; at o-saft.pl line 1662.
     **WARNING: ancient Net::SSLeay 1.35 < 1.49 detected; at o-saft.pl line 1687.
     **WARNING: ancient IO::Socket::SSL 1.22 < 1.37 detected; at o-saft.pl line 1687.
     **WARNING: ancient version IO::Socket::SSL 1.22 < 1.90 does not support SNI or is known to be buggy; SNI disabled; at o-saft.pl line 5905.
     !!Hint: --force-openssl can be used to disables this check
     **WARNING: ancient version Net::SSLeay 1.35 < 1.49  may throw warnings and/or results may be missing; at o-saft.pl line 5934.
     **WARNING: SSL version 'TLSv11': not supported by Net::SSLeay; not checked
     **WARNING: SSL version 'TLSv12': not supported by Net::SSLeay; not checked
     **WARNING: SSL version 'TLSv13': not supported by Net::SSLeay; not checked
     === o-saft.pl 16.09.09 ===
         Net::SSLeay::
            ::OPENSSL_VERSION_NUMBER()    0x9470143
     **WARNING: ancient version Net::SSLeay 1.35 < 1.49; cannot compare SSLeay with openssl version at o-saft.pl line 4778.
            ::SSLeay()                    0x1.35
     **WARNING: ancient version Net::SSLeay 1.35 < 1.49; detailed version not available at o-saft.pl line 4806.
     = openssl =
         version of external executable   OpenSSL 0.9.8y 5 Feb 2013
         external executable              /usr/bin/openssl
         used environment variable (name) LD_LIBRARY_PATH
         environment variable (content)   <<undef>>
         path to shared libraries
         full path to openssl.cnf file    <<undef>>
         common openssl.cnf files         /usr/lib/ssl/openssl.cnf \
                                          /etc/ssl/openssl.cnf \
                                          /System//Library/OpenSSL/openssl.cnf \
                                          /usr/ssl/openssl.cnf
         URL where to find CRL file       <<undef>>
         directory with PEM files for CAs /System/Library/OpenSSL/certs
         PEM format file with CAs         <<undef>>
         common paths to PEM files for CAs /etc/ssl/certs /usr/lib/certs /System/Library/OpenSSL
         common PEM filenames for CAs     ca-certificates.crt certificates.crt certs.pem
         number of supported ciphers      43
         openssl supported SSL versions   SSLv2 SSLv3 TLSv1
         o-saft.pl known SSL versions     SSLv2 SSLv3 TLSv1 TLSv11 TLSv12 TLSv13 \
                                          DTLSv09 DTLSv1 DTLSv11 DTLSv12 DTLSv13
     **WARNING: ancient version Net::SSLeay 1.35 < 1.49; cannot compare SSLeay with openssl version at o-saft.pl line 4778.
     **WARNING: used openssl version '9470143' differs from compiled Net:SSLeay '1.35'; ignored
     = o-saft.pl +cipherall =
         default list of ciphers          0x03000000 .. 0x030000FF, 0x0300C000 .. 0x0300C0FF,
                                          0x0300CC00 .. 0x0300CCFF, 0x0300FE00 .. 0x0300FFFF,
     = Required (and used) Modules =
         @INC                 ./ ./lib /bin /Library/Perl/Updates/5.10.0 \
                              /System/Library/Perl/5.10.0/darwin-thread-multi-2level \
                              /System/Library/Perl/5.10.0 \
                              /Library/Perl/5.10.0/darwin-thread-multi-2level \
                              /Library/Perl/5.10.0 \
                              /Network/Library/Perl/5.10.0/darwin-thread-multi-2level \
                              /Network/Library/Perl/5.10.0 \
                              /Network/Library/Perl \
                              /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level \
                              /System/Library/Perl/Extras/5.10.0 .
     =   module name            VERSION  found in
     =   ----------------------+--------+------------------------------------------
         IO::Socket::INET       1.31     /System/Library/Perl/5.10.0/darwin-thread-multi-2level/IO/Socket/INET.pm
         IO::Socket::SSL        1.22     /System/Library/Perl/Extras/5.10.0/IO/Socket/SSL.pm
         Net::DNS               0.65     /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level/Net/DNS.pm
         Net::SSLeay            1.35     /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level/Net/SSLeay.pm
         Net::SSLinfo           16.06.01 ./Net/SSLinfo.pm
         Net::SSLhello          16.05.16 ./Net/SSLhello.pm
         osaft                  16.05.10 /osaft.pm

Please keep in mind that the shown version numbers and the shown line

numbers are examples and may differ on your system.

When starting o-saft.pl with outdated modules, more **WARNING: will

be shown. The warnings depend on the installed version of the module.

o-saft.pl is known to work with at least:

IO::Socket::INET 1.31, IO::Socket::SSL 1.22, Net::DNS 0.66, Net::SSLeay 1.30

TESTING

When talking about "testing the tool", functionl tests are meant. So

this section describes "developer" rather than "user" options.

Testing the tool is a challenging task. Beside the oddities described

elsewhere, for example Name Rodeo, there are a bunch of problems

and error which may occour during runtime.

Makefiles are used for testing functionality and code quality during

development. These tests are implemented in the ./t/ directory, see

the Makefile.* there.

Following options and commands for o-saft.pl are available to improve

testing. They mainly can simulate error conditions or stop execution

properly (they are not intended for other use cases):

+quit

Stop execution after processing all arguments and before precessing

any target. The runtime configuration is complete at this point.

--exit=KEY

Terminate o-saft.pl at specified KEY. For available KEY please see:

   o-saft.pl --help=exit
   grep exit= o-saft.pl

--cfg-init=KEY=VALUE

With this option values in the internal %cfg hash can be set:

   $cfg{KEY} = VALUE

Only (perl) scalars or arrays can be set. The type will be detected

automatically.

Example, this option can be used to change the text used as prefix

in each output line triggerd by the --v option:

   o-saft.pl --cfg-init=prefix_verbose="#VERBOSE: "

or the text used as prefix triggerd by the --trace option:

   o-saft.pl --cfg-init=prefix_trace="#TRACE: "

--v

Print more information about checks.

--trace

Print debugging messages.

For more details, please see Options for tracing and debugging .

Internal testing

Following options and commands for o-saft.pl are for internal testing.

They provide informations about internal data structures and alike.

--test-data

Print overview of all available commands and checks.

--test-prot

Print internal data according protocols.

--test-regex

Print results for applying various texts to defined regex.

--test-cipher-list

Print list of hex keys of known ciphers.

--test-cipher-sorted

Print list of ciphers sorted according strength.

EXAMPLES

($0 in all following examples is the name of the tool)

General

   o-saft.pl +cipher some.tld
   o-saft.pl +info   some.tld
   o-saft.pl +check  some.tld
   o-saft.pl +quick  some.tld
   o-saft.pl +help=commands
   o-saft.pl +list
   o-saft.pl +list --v
   o-saft.pl +certificate  some.tld
   o-saft.pl +fingerprint  some.tld 444
   o-saft.pl +after +dates some.tld

Some Specials

Get an idea how messages look like

   o-saft.pl +check --cipher=RC4 some.tld

Check for Server Name Indication (SNI) usage only

   o-saft.pl +sni some.tld

Check for SNI and print certificate's subject and altname

   o-saft.pl +sni +cn +altname some.tld

Check for all SNI, certificate's subject and altname issues

   o-saft.pl +sni_check some.tld

Only print supported ciphers

   o-saft.pl +cipher --enabled some.tld

Only print unsupported ciphers

   o-saft.pl +cipher --disabled some.tld

Test for a specific ciphers

   o-saft.pl +cipher --cipher=ADH-AES256-SHA some.tld

Test all ciphers, even if not supported by local SSL implementation

   o-saft.pl +cipherraw some.tld
   o-saft.pl +cipherall some.tld
   o-saft.pl +cipherall some.tld --range=full
   checkAllCiphers.pl example.tld --range=full --v

Show supported (enabled) ciphers with their DH parameters:

   o-saft.pl +cipher-dh some.tld

Test using a private libssl.so, libcrypto.so and openssl

   o-saft.pl +cipher --lib=/foo/bar-1.42 --exe=/foo/bar-1.42/apps some.tld

Test using a private openssl

   o-saft.pl +cipher --openssl=/foo/bar-1.42/openssl some.tld

Test using a private openssl also for testing supported ciphers

   o-saft.pl +cipher --openssl=/foo/bar-1.42/openssl --force-openssl some.tld

Show current score settings

   o-saft.pl --help=score

Change a single score setting

   o-saft.pl --cfg_score=http_https=42   +check some.tld

Use your private score settings from a file

   o-saft.pl --help=score > magic.score

# edit as needed: magic.score

   o-saft.pl --cfg_score    magic.score  +check some.tld

Use your private texts in output

   o-saft.pl +check some.tld --cfg_text=desc=my special description

Use your private texts from RC-FILE

   o-saft.pl --help=cfg_text >> .o-saft.pl

# edit as needed: .o-saft.pl

   o-saft.pl +check some.tld

Use your private hint texts in output

   o-saft.pl +check some.tld --cfg-hint=renegotiation="my special hint text"

Get the certificate's Common Name for a bunch of servers:

   o-saft.pl +cn example.tld some.tld other.tld
   o-saft.pl +cn example.tld some.tld other.tld --showhost --no-header

Generate simple parsable output

   o-saft.pl --legacy=quick --no-header +info  some.tld
   o-saft.pl --legacy=quick --no-header +check some.tld
   o-saft.pl --legacy=quick --no-header --trace-key +info  some.tld
   o-saft.pl --legacy=quick --no-header --trace-key +check some.tld

Generate simple parsable output for multiple hosts

   o-saft.pl --legacy=quick --no-header --trace-key --showhost +check some.tld other.tld

Just for curiosity

   o-saft.pl some.tld +fingerprint --format=raw
   o-saft.pl some.tld +certificate --format=raw | openssl x509 -noout -fingerprint

Testing with exit code

Test SSL/TLS connection and return exit code

   o-saft.pl +check  --exitcode  some.tld

Test ciphers and return exit code with details about exit code

   o-saft.pl +cipher --exitcode --exitcode-v  some.tld

Test ciphers and return exit code for ciphers only

   o-saft.pl +cipher --exitcode --exitcode-no-prot  some.tld

Test with exit code but avoid checks considered 'yes' even if 'no'

   o-saft.pl +check  --exitcode --ignore-out=ev- --ignore-out=rfc_7525 some.tld

Specials for hunting problems with connections etc.

Show command line argument processing

   o-saft.pl +info some.tld --trace-arg

Simple tracing

   o-saft.pl +cn   some.tld --trace
   o-saft.pl +info some.tld --trace

A bit more tracing

   o-saft.pl +cn   some.tld --trace --trace

Show internal variable names in output

   o-saft.pl +info some.tld --trace-key

Show internal argument processeing

   o-saft.pl +info --trace-arg some.tld

Show internal control flow

   o-saft.pl +info some.tld --trace-cmd

Show internal timing

   o-saft.pl +info some.tld --trace-time

Show checking ciphers

   o-saft.pl +cipher some.tld --v --v

Show values retrieved from target certificate directly

   o-saft.pl +info some.tld --no-cert --no-cert --no-cert-text=Value-from-Certificate

Show certificate CA verifications

   o-saft.pl some.tld +chain_verify +verify +error_verify +chain

Avoid most performance and timeout problems (don't use --v)

   o-saft.pl +info some.tld --no-dns --no-sni --ignore-no-conn
   o-saft.pl +info some.tld --no-dns --no-sni --no-cert --no-http --no-openssl

Identify timeout problems

   o-saft.pl +info some.tld --trace-cmd

this will show lines containing:

    #O-Saft  CMD: test ...

ATTRIBUTION

Based on ideas (in alphabetical order) of:

cnark.pl, SSLAudit.pl sslscan, ssltest.pl, sslyze.py, testssl.sh

O-Saft - OWASP SSL advanced forensic tool

Thanks to Gregor Kuznik for this title.

cipherraw and most proxy functionality implemented by Torsten Gigler.

For re-writing some docs in proper English, thanks to Robb Watson.

Code to check heartbleed vulnerability adapted from

Steffen Ullrich (08. April 2014):

https://github.com/noxxi/p5-scripts/blob/master/check-ssl-heartbleed.pl

Colouration inspired by https://testssl.sh/ .

AUTHOR

Achim Hoffmann

VERSION

@(#) 16.09.16

Content of this wiki page generated with:

o-saft.pl --no-warning --no-header --help=gen-wiki

@@ Line 164: / Line 164: @@
 =====Results=====
-:Results of checks are marked  <code>yes</code>  or <code>no</code>.  This leaves the prop
+:Results of checks are marked  <code>yes</code>  or <code>no</code>.  This leaves the proper
-er
 :interpretation, if the result is "good" or "bad", to the user.
 :Background:  it is not always possible to rate a result as  "good" or
@@ Line 171: / Line 170: @@
 :"the best" or a "proper" recomendation. In practice it depends on the
 :context what a recomendation, or countermeasure should be. That's why
-:all results are marked  <code>yes</code>  or  <code>no</code>  if considered "questionabl
+:all results are marked  <code>yes</code>  or  <code>no</code>  if considered "questionable"
-e"
 :or "not good" (for example according other checks).