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V-233562

CAT II (Medium)

PostgreSQL must be able to generate audit records when privileges/permissions are retrieved.

Rule ID

SV-233562r960885_rule

STIG

Crunchy Data PostgreSQL Security Technical Implementation Guide

Version

V3R1

CCIs

CCI-000172

Discussion

Under some circumstances, it may be useful to monitor who/what is reading privilege/permission/role information. Therefore, it must be possible to configure auditing to do this. PostgreSQLs typically make such information available through views or functions. This requirement addresses explicit requests for privilege/permission/role membership information. It does not refer to the implicit retrieval of privileges/permissions/role memberships that PostgreSQL continually performs to determine if any and every action on the database is permitted.

Check Content

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

First, as the database administrator (shown here as "postgres"), check if pgaudit is enabled by running the following SQL:

$ sudo su - postgres
$ psql -c "SHOW shared_preload_libraries"

If pgaudit is not found in the results, this is a finding.

Next, as the database administrator (shown here as "postgres"), list all role memberships for the database:

$ sudo su - postgres
$ psql -c "\du"

Next, verify the query was logged:

$ sudo su - postgres
$ cat ${PGLOG?}/<latest_log>

This should, as an example, return (among other rows):
2016-01-28 19:43:12.126 UTC postgres postgres: >LOG: AUDIT: SESSION,1,1,READ,SELECT,,,"SELECT r.rolname, r.rolsuper, r.rolinherit,
r.rolcreaterole, r.rolcreatedb, r.rolcanlogin,
r.rolconnlimit, r.rolvaliduntil,
ARRAY(SELECT b.rolname
FROM pg_catalog.pg_auth_members m
JOIN pg_catalog.pg_roles b ON (m.roleid = b.oid)
WHERE m.member = r.oid) as memberof
, r.rolreplication
, r.rolbypassrls
FROM pg_catalog.pg_roles r
ORDER BY 1;",<none>

If audit records are not produced, this is a finding.

Fix Text

Note: The following instructions use the PGDATA and PGVER environment variables. See supplementary content APPENDIX-F for instructions on configuring PGDATA and APPENDIX-H for PGVER.

Using pgaudit PostgreSQL can be configured to audit these requests. See supplementary content APPENDIX-B for documentation on installing pgaudit.

With pgaudit installed the following configurations can be made:

$ sudo su - postgres
$ vi ${PGDATA?}/postgresql.conf

Add the following parameters (or edit existing parameters): 

pgaudit.log_catalog = 'on'
pgaudit.log = 'read'

Now, as the system administrator, reload the server with the new configuration:

$ sudo systemctl reload postgresql-${PGVER?}