Title

Execution of software modules (to include stored procedures, functions, and triggers) with elevated privileges must be restricted to necessary cases only. (Cat II impact)

Discussion

In certain situations, to provide required functionality, a DBMS needs to execute internal logic (stored procedures, functions, triggers, etc.) and/or external code modules with elevated privileges. However, if the privileges required for execution are at a higher level than the privileges assigned to organizational users invoking the functionality applications/programs, those users are indirectly provided with greater privileges than assigned by organizations. Privilege elevation must be utilized only where necessary and protected from misuse. This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

Check Content

Review the system documentation and source code of the application(s) using the database. If elevation of DBMS privileges is used but not documented, this is a finding. If elevation of DBMS privileges is documented but not implemented as described in the documentation, this is a finding. If the privilege-elevation logic can be invoked in ways other than intended, in contexts other than intended, or by subjects/principals other than intended, this is a finding. Execute the following SQL as the "enterprisedb" operating system user to find any SECURITY DEFINER functions (meaning they are executed as owner rather than invoker): psql edb -c "SELECT proname FROM pg_proc WHERE prosecdef = true" If any of these functions should not be SECURITY DEFINER, this is a finding.

Fix Text

Determine where, when, how, and by what principals/subjects elevated privilege is needed. Modify the system and the application(s) using the database to ensure privilege elevation is used only as required. To alter a function to use SECURITY INVOKER instead of SECURITY DEFINER, execute the following SQL as the "enterprisedb" user: ALTER FUNCTION <function()> SECURITY INVOKER;

Additional Identifiers

Rule ID: SV-259274r938875_rule

Vulnerability ID: V-259274

Group Title: SRG-APP-000342-DB-000302

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.