PGS9-00-011700 - PostgreSQL must prevent non-privileged users from executing privileged functions, to include disabling, circumventing, or altering implemented security safeguards/countermeasures.

Information

Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges.

System documentation should include a definition of the functionality considered privileged.

Depending on circumstances, privileged functions can include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.

A privileged function in PostgreSQL/database context is any operation that modifies the structure of the database, its built-in logic, or its security settings. This would include all Data Definition Language (DDL) statements and all security-related statements. In an SQL environment, it encompasses, but is not necessarily limited to:

CREATE
ALTER
DROP
GRANT
REVOKE

There may also be Data Manipulation Language (DML) statements that, subject to context, should be regarded as privileged. Possible examples include:

TRUNCATE TABLE;
DELETE, or
DELETE affecting more than n rows, for some n, or
DELETE without a WHERE clause;

UPDATE or
UPDATE affecting more than n rows, for some n, or
UPDATE without a WHERE clause;

any SELECT, INSERT, UPDATE, or DELETE to an application-defined security table executed by other than a security principal.

Depending on the capabilities of PostgreSQL and the design of the database and associated applications, the prevention of unauthorized use of privileged functions may be achieved by means of DBMS security features, database triggers, other mechanisms, or a combination of these.

However, the use of procedural languages within PostgreSQL, such as pl/R and pl/Python, introduce security risk. Any user on the PostgreSQL who is granted access to pl/R or pl/Python is able to run UDFs to escalate privileges and perform unintended functions. Procedural languages such as pl/Perl and pl/Java have 'untrusted' mode of operation, which do not allow a non-privileged PostgreSQL user to escalate privileges or perform actions as a database administrator.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

Configure PostgreSQL security to protect all privileged functionality.

If pl/R and pl/Python are used, document their intended use, document users that have access to pl/R and pl/Python, as well as their business use case, such as data-analytics or data-mining. Because of the risks associated with using pl/R and pl/Python, their use must have AO risk acceptance.

To remove unwanted extensions, use:

DROP EXTENSION <extension_name>

To remove unwanted privileges from a role, use the REVOKE command.

See the PostgreSQL documentation for more details: http://www.postgresql.org/docs/current/static/sql-revoke.html

Item Details

Audit Name: DISA STIG PostgreSQL 9.x on RHEL DB v2r5

Category: ACCESS CONTROL

Plugin: PostgreSQLDB

Control ID: 5f6121e5f2b16b0e85480e2e0b57e116e6de3aedf07b3d176810c3531fa5ffd1

Detections

Analytics

PGS9-00-011700 - PostgreSQL must prevent non-privileged users from executing privileged functions, to include disabling, circumventing, or altering implemented security safeguards/countermeasures.

Information

Solution

See Also

Item Details