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=== Inbound connection timeout ===
 
=== Inbound connection timeout ===
  
The controls of the amount of time, in second, the listener waits for a network client to complete the connection request should be configure to prevent a denial of service attack.
+
The controls of the amount of time the listener waits for a network client to complete the connection request should be manage to prevent a denial of service attack.
The name of parameter, to set to configure inbound connection timeout and the name of the file to add it, depends on Oracle version.
+
The name of parameter to set to configure inbound connection timeout and the name of the file of configuration, depends on Oracle version.
This parameter protects the listener from consuming and holding resources for client connection requests that do not complete. A malicious user could use this to flood the listener with requests that result in a denial of service to authorized users.
 
To prevent this, secify, also, the expire_time parameter probes for dead connections and terminates them when found. This setting does cause a slight increase in network traffic.
 
  
 
== Packages, procedures and functions ==
 
== Packages, procedures and functions ==

Revision as of 15:28, 29 May 2008

Overview

Description

Installation security

This section is useful to understand how the installation will introduce vulnerabilities if it is not made “security oriented”.

Options and products

The Oracle Database installation pack contains a lot of options and products beside to the database server, so a custom installation should be done to avoid installing options and products not needed. The Oracle components other than the list below should be removed if not specifically required by any database applications.


Oracle database components
Assistant Common Files
Generic Connectivity Common Files
Generic Connectivity Using Open Database Connectivity (ODBC)
Oracle Net
Oracle Net Listener
Oracle Net Manager
Oracle Net Required Support Files
Oracle Net Services
Oracle Core Required Support Files
Oracle Call Interface
Oracle9i/8i/10g
Oracle9i/8i/10g Database
Oracle9i/8i/10g Development Kit
Oracle9i/8i/10g Windows Documentation (Windows only)
Parser Generator Required Support Files
Programming Language / Structured Query Language (PL/SQL)
PL/SQL Embedded Gateway
PL/SQL Required Support Files
Platform Required Support Files
Relational Database Management System (RDBMS) Required Support Files
Required Support Files

Sample schemas

Oracle Corporation provides sample schemas in order to provide a common platform for examples. Review, after the installation, installed schema and remove any schema you do not need, using the follow SQL statement:

  SQL> DROP USER <user_name> CASCADE;

Patching

Apply, always, all security patches for Oracle Database itself, and for all the options and components that are installed. Periodically check the security site on Oracle Technology Network for details on security alerts released by Oracle Corporation:

                                    http://otn.oracle.com/deploy/security/alerts.htm

Further, if you subscribe the security mailing lists you will be able to catch any new security issues that are not reported to Oracle but are announced to the public (maybe without a patch). In such cases, it will be relevant to find a way to mitigate the risk of the new vulnerability in the absence of an Oracle-supplied patch.

Initialization parameters

This section cover the Oracle Initialization parameters that are relevant for the security aspects. All the following initialization parameters have to be specified for all Oracle instances.

Parameter name Description Security value
REMOTE_OS_AUTHENTICATION This parameter, when set to TRUE, allows the authentication of remote clients by the host operating system. The default value for this parameter is FALSE. This parameter will remain set to FALSE because of the risk of an impersonation attack, otherwise known as spoofing. FALSE
REMOTE_LOGIN_PASSWORDFILE Specifies whether Oracle uses a password file and, if in use, how many databases can use the password file. Setting the parameter to EXCLUSIVE signifies that the password file can be used by only one database. The password file requires remote DBAs to use their own individual DBA accounts to authenticate to the database for administrative database operations. EXCLUSIVE
RESOURCE_LIMIT Specifies whether or not enforcement of resource limits is enabled. If not enabled, the required idle time limits would not be enforced. The default is FALSE. TRUE
REMOTE_OS_ROLES Allow operating system roles to be used from remote clients. FALSE
OS_ROLES Determines whether Oracle or the operating system identifies and manages the roles of each username.

Set to FALSE to configure Oracle to identifies and manages the roles. Default value false.

FALSE
UTL_FILE_DIR Specifies one or more directories that Oracle should use for PL/SQL

file I/O.

NULL
AUDIT_SYS_OPERATIONS Enables or disables the auditing of operations issued by user SYS, and users connecting with SYSDBA or SYSOPER privileges. The audit records are written to the operating system's audit trail if the AUDIT_TRAIL initialization parameter is set to OS. The default is FALSE. TRUE
AUDIT_TRAIL Enables or disables database auditing. Default value none. OS
AUDIT_FILE_DEST (UNIX only) Specifies the operating system directory into which the audit trail is written when the AUDIT_TRAIL initialization parameter is set to os, xml (extended and not).

The audit records will be written in XML format if the AUDIT_TRAIL initialization parameter is set to XML. It is also the location to which mandatory auditing information is written and, if so specified by the AUDIT_SYS_OPERATIONS initialization parameter, audit records for user SYS.

<Protected Directory>
USER_DUMP_DEST Specifies the pathname for a directory where the server will write debugging trace files on behalf of a user process. <Protected Directory>
BACKGROUND_DUMP_DEST Specifies the pathname (directory or disk) where debugging trace files for the background processes (LGWR, DBWn, and so on) are written during Oracle operations. <Protected Directory>
CORE_DUMP_DEST Specifies the directory where Oracle dumps core files. <Protected Directory>
07_DICTIONARY_ACCESSIBILITY Controls restrictions on SYSTEM privileges. If this parameter is set to FALSE, SYSTEM privileges that allow access to objects in other schemas do not allow access to objects in the dictionary or SYS schema. FALSE

Example SQL for setting the REMOTE_OS_AUTHENTICATION parameter:

  SQL> ALTER SYSTEM SET REMOTE_OS_AUTHENTICATION = FALSE SCOPE=BOTH

Scope:

  • MEMORY: This value change the instance immediately, but the configuration is lost after a restart.
  • SPFILE: This value NOT change the instance immediately, but a restart is necessaty to take effect.
  • BOTH: This value change the instance immediately as well as the spfile.

Operating system security

Owner account

The Oracle OS installation account, owner of all Oracle application and datafiles, should be used only for the update and maintenance of the Oracle software and will not be used during the standard DBA activities. The individual DBAs will have to use their assigned OS personal accounts, so the auditing process will be able to actions performed with the correct OS account. The Oracle software installation account will not be a member of the administrative group.

Files and directories

All files and directories generated during the installation process of Oracle will be restricted to the Oracle software owner or the DBA OS user group, especially the file list below:

File name Description
init.ora and/or init<SID>.ora

Spfile.ora

The file houses Oracle initialization parameter files. Replace SID with the name of your SID.
orapw<SID> The file contain SYS password and the password of accounts granted the SYSDBA or SYSOPER role. Replace SID with the name of your SID.
listener.ora The file houses listener configuration parameters and password.
snmp_rw.ora The file contains the password for the DBSNMP database account in cleartext.
snmp_ro.ora The file houses configuration information for the Oracle Intelligent Agent.
sqlnet.ora The file contains network configuration information for the host database and listener.

Other accounts should be denied access except to executables under the “bin” directory as specifically required. All files stored in the “bin” directory will be owned by the Oracle software installation account. These files and directories will be secured by using access control methods native to the operating system.

Account management

Lock and expire unused accounts

A number of default database server user accounts are create during the installation process so, if you do not use the Database Configuration Assistant, you should lock and expire all default database user accounts. Unlock only those accounts that need to be accessed on a regular basis and assign a strong password to each of these unlocked accounts.

Example SQL for reviewing the Oracle Default Accounts with status “OPEN”:

  SQL> SELECT <user_name> FROM dba_users WHERE account_status <> ’OPEN’ ORDER BY <user_name>;

Example SQL for Locking Accounts:

  SQL> ALTER USER <user_name> ACCOUNT LOCK;

Change default password

The major weakness concerning the password is that some user default account, after the installation, still has a default password associated with it, so you should be review the passwords of all default accounts (SYS, SYSTEM, DBSNMP, OUTLN and so on) and change it if necessary.

Enforce password policy

The password policy should be enforced by password verification function setting password parameter (list below) and providing password complexity feature like minimum length, password not same as the username, the password contains repeating characters, the password differs from the previous password by at least a maximal number of letters.

Example SQL for setting a password verification function to a profile:

  SQL> CREATE PROFILE <profile_name> LIMIT PASSWORD_VERIFICATION_FUCTION <newvalue>

Example SQL for assigning profile profile to a user:

  SQL> CREATE USER <user_name> IDENTIFIED BY <password> PROFILE <profile_name>;

Roles

Automated processing database accounts

Network security

Encrypt network logins

The password information in a connection request should be encrypted to protect against network eavesdropping. The value of the follow parameter should be review:

  ORA_ENCRYPT_LOGIN (on the client machine)
  DBLINK_ENCRYPT_LOGIN (on the server machine)

Once these parameters have been set to TRUE, passwords will be encrypted in connection requests. Note that on Oracle version 9.02 and later these parameter are not available, in fact it is encrypt automatically the password information when transmitting over a network, although the setting or changing of passwords is NOT encrypted when across the network.

Protect network communications

It is a good idea use the Oracle Advanced Security to use Secure Socket Layer (SSL) as to encrypt network traffic between clients and databases. Enable the protection about network communication by following the next step:

  ...

XML database (XDB) protocol server

The XML Database (XDB) offers access to the Oracle XML DB resources using the standard Internet protocols FTP, listening on TCP port 2100, and HTTP, listening on TCP port 8080. The Oracle XML DB Protocol Server is a specific type of Oracle shared server dispatcher and is specified in the Oracle database initialization parameter file for startup, so if XDB is not used it should be turned off editing the init<SID>.ora or spfile<SID>.ora (replace SID with the name of your SID) file and remove or comment the follow line:

 dispatchers="(PROTOCOL=TCP) (SERVICE=<SID>XDB)"

If access via the Internet protocols is required, logging should be enabled by setting the “ftp-log-level” and “http-log-level” parameters to a value of 1 in xdbconfig.xml file.

Oracle TNS Listner security

Password

A listener password should be set at the end of listener configuration process to avoid from unauthorized start, stop, and configure. The password will be stored in encrypted format within the listener.ora file by using the LSNRCTL utility:

  LSNRCTL> set current_listener <listener_name>
  LNSRCTL> set password
  Password: (type "enter" if it is the first time)
  The command completed successfully
  LSNRCTL> change_password
  Old password: (type "enter")
  New password: <new_password>
  Reenter new password: <new_password>
  […]
  The command completed successfully
  LSNRCTL> save_config (important to save the configuration)
  […]
  Saved LISTENER configuration parameters.
  Listener Parameter File […]
  Old Parameter File […]
  The command completed successfully
  LSNRCTL> exit

Admin restrictions

The remote administration of the Oracle listener should be prevent by setting to TRUE the ADMIN_RESTRICTIONS parameter in the listener.ora file:

  ADMIN_RESTRICTIONS_<listener_name> = TRUE

Replace listener_name with the name of your listener.

This will require that any configuration changes be made to the listener through direct edits to the listener.ora file.

Network address restriction

The network address restrictions should be enforced by the Oracle listener to further protect your database from unauthorized remote access. Network address restriction is required when the PLSQL EXTPROC is in use to protect against unauthenticated access to the database. To enable network address restriction, edit the SQLNET.ORA to add the follow line:

  TCP.VALIDNODE_CHECKING = YES

Then, to defines TCP/IP addresses that are allowed to connect to database add the follow line:

  TCP.INVITED_NODES = <list of IP addresses>

At the end, to defines TCP/IP addresses that are refused connections to the database set the follow parameter

  TCP.EXCLUDED_NODES = <list of IP addresses>

External procedures

Inbound connection timeout

The controls of the amount of time the listener waits for a network client to complete the connection request should be manage to prevent a denial of service attack. The name of parameter to set to configure inbound connection timeout and the name of the file of configuration, depends on Oracle version.

Packages, procedures and functions

Audit

References

[1] The Oracle Hacker's Handbook: Hacking and Defending Oracle by David Litchfield

[2] The Database Hacker's Handbook: Defending Database Servers by David Litchfield

[3] Database Security Technical Implementation Guide by DISA for the DOD

[4] Oracle Database Security Guide by Oracle Corporation

[5] Oracle Database Security Checklist by Oracle Corporation