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V-261957

CAT II (Medium)

PostgreSQL must generate audit records when unsuccessful logons or connection attempts occur.

Rule ID

SV-261957r1000876_rule

STIG

Crunchy Data Postgres 16 Security Technical Implementation Guide

Version

V1R2

CCIs

CCI-000172

Discussion

For completeness of forensic analysis, it is necessary to track failed attempts to log on to PostgreSQL. While positive identification may not be possible in a case of failed authentication, as much information as possible about the incident must be captured.

Check Content

Note: The following instructions use the PGDATA and PGLOG environment variables. Refer to APPENDIX-F for instructions on configuring PGDATA and APPENDIX-I on PGLOG.

In this example the user "joe" will log in to the Postgres database unsuccessfully:

$ psql -d postgres -U joe

As the database administrator (shown here as "postgres"), check ${PGLOG?} for a FATAL connection audit trail:

$ sudo su - postgres
$ cat ${PGDATA?}/${PGLOG?}/{latest_log>
< 2024-02-16 16:18:13.027 UTC joe 56c65135.b5f postgres: >LOG: connection authorized: user=joe database=postgres
< 2024-02-16 16:18:13.027 UTC joe 56c65135.b5f postgres: >FATAL: role "joe" does not exist

If an audit record is not generated each time a user (or other principal) attempts, but fails to log on or connect to PostgreSQL (including attempts where the user ID is invalid/unknown), this is a finding.

Fix Text

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

To ensure logging is enabled, see the instructions in the supplementary content APPENDIX-C.

If logging is enabled the following configurations must be made to log unsuccessful connections, date/time, username, and session identifier.

As the database administrator (shown here as "postgres"), edit postgresql.conf:

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

Edit the following parameters:

log_connections = on
log_line_prefix = '< %m %u %c: >'

Where:
* %m is the time and date
* %u is the username
* %c is the session ID for the connection

As the system administrator, reload the server with the new configuration:

$ sudo systemctl reload postgresql-${PGVER?}