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Difference between revisions of "OWASP Backend Security Project DB2 Hardening"

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* DBADM authorisation;
 
* DBADM authorisation;
 
* A privilege with a Grant option (right to grant privileges to other groups or users).
 
* A privilege with a Grant option (right to grant privileges to other groups or users).
−
For example: it is possible to grant ALTERIN privileges on a schema using one of these authorisations:
+
 
 +
For example, it is possible to grant ALTERIN privileges on a schema using one of these authorisations:
 +
 
 
* SYSADM authorisation;
 
* SYSADM authorisation;
 
* DBADM authorisation on the database where the schema is located;
 
* DBADM authorisation on the database where the schema is located;
 
* ALTERIN privileges on the schema together with the right to grant this schema privilege to other users or groups.
 
* ALTERIN privileges on the schema together with the right to grant this schema privilege to other users or groups.
 
|-
 
|-
−
|  
+
| Granting or revoking privileges on catalogue views and tables ||
 +
* SYSADM or DBADM authorisation is required.
 +
|-
 +
| Granting and revoking the CONTROL privileges on user-defined views and tables ||
 +
* SYSADM or DBADM authorisation is required.
 +
|-
 +
| Granting privileges different than CONTROL on user-defined views and tables ||
 +
One of the following authorisations is required:
 +
* SYSADM authorisation;
 +
* DBADM authorisation;
 +
* The CONTROL privilege on the tables or views over which you want to grant privileges;
 +
* The privilege that you want to grant together with the  Grant option (the right to grant this privilege to other users or groups).
 +
 
 +
For example: it is possible to grant the ALTER privilege on the user-defined table using one of the following authorisations:
 +
* SYSADM authorisation;
 +
* DBADM authorisation on the database where the table is located;
 +
* The CONTROL privilege on the table;
 +
* The ALTER privilege, together with the right to grant this privilege on the table to other users or groups.
 +
|-
 +
| Revoking privileges different than CONTROL on user-defined views and tables ||
 +
One of the following authorisations is required:
 +
* SYSADM authorisation;
 +
* DBADM authorisation;
 +
* The CONTROL privilege on the tables or views over which you want to grant privileges;
 
|}
 
|}
  

Revision as of 14:12, 2 June 2008

Overview

Historically DB2 has lived on a mainframe and resided in a fairly secure network. More and more we see DB2 exposed to the large world and used as backend for web applications. With these changes in DB2 comes increased risk.

This paragraph has the objectives to define the minimum security requirements for configuring and managing DB2 databases, in terms of access to, configuration and management of the system, and to supply guidelines and operation instructions for system administrators, in order to guarantee the development of secure applications on DB2 platforms.

Description

Configuring Accounts and Groups

Unlike Oracle and Microsoft SQL Server, which support database authentication and database accounts, DB2 exclusively uses the operating system for authentication purposes. What this means is that DB2 is immune to attackers gaining access via database accounts without a password, or accounts that have a default password. Indeed, when DB2 is installed some OS accounts are created and, in earlier versions of DB2, these OS accounts were given default passwords.

DB2 accounts must be subject to the same control and administration rules as other accounts in operating systems. In particular, you must verify if accounts are redundant or have not been used at least once. Database administrators must periodically verify and possibly rectify privileges, groups and functions assigned to accounts, in order to guarantee that permissions assigned to users correspond to their real working needs.

Ensure you have enabled password management features with for example a password lockout to 10 and password expiration to 90 days. The account expiration date must be set for accounts for users whose period of work is defined and limited in time.

*NIX platforms

It is advisable to change the default user-ids installed at the moment of database installation or by 3rd party products. By default, the DB2 Setup wizard creates these user and group accounts automatically during a DB2 UDB server installation. Installed with the database there are some DB2 users (db2inst1, db2fenc1, and dasusr1): 

 db2inst1:x:1001:1001::/home/db2inst1:/bin/sh
 db2fenc1:x:1002:1002::/home/db2fenc1:/bin/sh
 dasusr1:x:1003:1003::/home/dasusr1:/bin/sh

You need to modify the initial passwords (ibmdb2). To do this, run these three commands: 

 passwd db2inst1
 passwd db2fenc1
 passwd dasusr1

Some others accounts could be present after database or 3rd party products installation, they are: 

 db2inst[n]/ibmdb2        0 < n < 10        (db2inst2, db2inst3, ..., db2inst9)
 db2fenc[n]/ibmdb2        0 < n < 10        (db2fenc2, db2fenc3, ..., db2fenc9)
 db2ins[n]/ibmdb2         9 < n < 100       (db2ins10, db2ins11, ..., db2ins99)
 db2fen[n]/ibmdb2         9 < n < 100       (db2fen10, db2fen11, ..., db2fen99) 
 db2as/ibmdb2
 dlfm/ibmdb2
 db2admin/db2admin

It is advisable to change all the default password.

Windows platforms

Beginning in DB2 UDB Version 8.2, a security option was added as part of the DB2 UDB installation to create two additional groups in the operating system, DB2USERS and DB2ADMNS. Once these groups are created, only user accounts that are members of these groups will have access to the DB2 UDB files on the system (including commands as well as user data files created by DB2 UDB). 

 DB2ADMNS     this group and local managers have complete access to DB2 objects through the operating system
 DB2USERS     this group has read and execution access to the DB2 objects through the operating system

Ensure you have changed default password for db2admin account and you have enabled this option during the original DB2 UDB installation. You can always enable it at a later time by running the db2secv82.exe program. This program can be found in the DB2PATH\SQLLIB\BIN\ directory, where DB2PATH is the location where DB2 UDB was installed. You should enable this option in order to secure your server to the greatest extent.

Configuring Authentication

Authentication parameters

Encryption during Authentication

Configuring Authorisations

The appropriate authorisations allowed to the previously created user must be chosen by indicating which authorisations database you want to grant.

One or more authorisations can be allowed, according to the real need for the following privileges: 

 schema privileges 
 table privileges 
 index privileges 
 view privileges 
 tablespace privileges 
 function privileges 
 procedure privileges 
 method privileges 
 package privileges

In order to facilitate the process of monitoring accounts and their relative authorisations, DB2 automatically manages this information using its system catalogue containing the following views:

View name Description
SYSCAT.DBAUTH lists authorisations inherent to the database
SYSCAT.TABAUTH lists authorisations inherent to tables and views
SYSCAT.COLAUTH lists authorisations inherent to columns
SYSCAT.PACKAGEAUTH lists authorisations inherent to packages
SYSCAT.INDEXAUTH lists authorisations inherent to indexes
SYSCAT.SCHEMAAUTH lists authorisations inherent to schemas
SYSCAT.PASSTHRUAUTH lists authorisations inherent to servers
SYSCAT.ROUTINEAUTH lists authorisations inherent to routines (functions, methods, or stored procedures)

Assigning privileges

Each user with privileges of SYSDBA, SYSCTL, and SYSMAINT or comparable privileges can access and modify any object in the database. Consequently, these privileges must be assigned with extreme caution and strict criteria. The groups SYSDBA, SYSCTL, and SYSMAINT must be assigned only to users that carry out roles of administration of the database. The principle of assigning the minimum privileges that are strictly necessary in order to carry out the work must always be followed in all environments, also in the “less formal” development ones. The roles and privileges of all users in a database in a development environment must be recertified during migration to a production environment, in order to guarantee the validity of roles and privileges. Grants to GUEST users or PUBLIC groups must be avoided.

The following privileges must never be assigned to an application, except in specific, extraordinary circumstances: 

 BINDADD
 CREATETAB
 CREATE_EXTERNAL_ROUTINE
 CREATE_NOT_FENCED_ROUTINE
 IMPLICIT_SCHEMA
 LOAD
 QUIESCE_CONNECT

Database views must be defined in accordance with the roles defined by the application, and respecting the principle of the minimum privileges that are strictly necessary.

Action Authorisations and privileges
Granting or revoking database authorisations

The correct authorisations are required:

  • For granting BINDADD, CONNECT, CREATETAB, CREATE_NOT_FENCED and IMPLICIT_SCHEMA authorisations, SYSADM or DBADM authorisation is not required;
  • For granting DBADM authorisation, SYSADM authorisation is required.
Granting or revoking schema privileges

One of the following authorisations is required:

  • SYSADM authorisation;
  • DBADM authorisation;
  • A privilege with a Grant option (right to grant privileges to other groups or users).

For example, it is possible to grant ALTERIN privileges on a schema using one of these authorisations:

  • SYSADM authorisation;
  • DBADM authorisation on the database where the schema is located;
  • ALTERIN privileges on the schema together with the right to grant this schema privilege to other users or groups.
Granting or revoking privileges on catalogue views and tables
  • SYSADM or DBADM authorisation is required.
Granting and revoking the CONTROL privileges on user-defined views and tables
  • SYSADM or DBADM authorisation is required.
Granting privileges different than CONTROL on user-defined views and tables

One of the following authorisations is required:

  • SYSADM authorisation;
  • DBADM authorisation;
  • The CONTROL privilege on the tables or views over which you want to grant privileges;
  • The privilege that you want to grant together with the Grant option (the right to grant this privilege to other users or groups).

For example: it is possible to grant the ALTER privilege on the user-defined table using one of the following authorisations:

  • SYSADM authorisation;
  • DBADM authorisation on the database where the table is located;
  • The CONTROL privilege on the table;
  • The ALTER privilege, together with the right to grant this privilege on the table to other users or groups.
Revoking privileges different than CONTROL on user-defined views and tables

One of the following authorisations is required:

  • SYSADM authorisation;
  • DBADM authorisation;
  • The CONTROL privilege on the tables or views over which you want to grant privileges;

Authorisations and privileges on DB groups

Roles, Views and Access controls

Database Management System Configuration

File Permission

Administration

Auditing & Monitoring

Triggers

DB2 Universal Database audit facility

Auditing Events

References

  • DB2 Security and Compliance Solutions for Linux, UNIX, and Windows - Whei-Jen Chen, Ivo Rytir, Paul Read, Rafat Odeh - IBM Redbooks
  • Hardening DB2 - Giuseppe Gottardi - Internal at Communication Valley S.p.A.
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