V-214090

Discussion

Changes in the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized elevation or restriction of privileges could go undetected. Elevated privileges give users access to information and functionality that they should not have; restricted privileges wrongly deny access to authorized users. In an SQL environment, adding permissions is typically done via the GRANT command, or, in the negative, the REVOKE command.

Check Content

Note: The following instructions use the PGDATA environment variable. See supplementary content APPENDIX-F for instructions on configuring PGDATA.

First, as the database administrator (shown here as "postgres"), create a role by running the following SQL:

Change the privileges of another user:

$ sudo su - postgres
$ psql -c "CREATE ROLE bob"

Next, GRANT then REVOKE privileges from the role:

$ psql -c "GRANT CONNECT ON DATABASE postgres TO bob"
$ psql -c "REVOKE CONNECT ON DATABASE postgres FROM bob"

postgres=# REVOKE CONNECT ON DATABASE postgres FROM bob;
REVOKE

postgres=# GRANT CONNECT ON DATABASE postgres TO bob;
GRANT

Now, as the database administrator (shown here as "postgres"), verify the events were logged:

$ sudo su - postgres
$ cat ${PGDATA?}/pg_log/<latest_log>
< 2016-07-13 16:25:21.103 EDT postgres postgres LOG: > AUDIT: SESSION,1,1,ROLE,GRANT,,,GRANT CONNECT ON DATABASE postgres TO bob,<none>
< 2016-07-13 16:25:25.520 EDT postgres postgres LOG: > AUDIT: SESSION,1,1,ROLE,REVOKE,,,REVOKE CONNECT ON DATABASE postgres FROM bob,<none>

If the above steps cannot verify that audit records are produced when privileges/permissions/role memberships are added, this is a finding.