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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72923	PGS9-00-004600	SV-87575r2_rule		Medium

Description
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.

STIG	Date
PostgreSQL 9.x Security Technical Implementation Guide	2018-09-19

Details

Check Text ( C-73057r1_chk )
Note: The following instructions use the PGDATA environment variable. See supplementary content APPENDIX-F for instructions on configuring PGDATA. In this example the user joe will log into the Postgres database unsuccessfully: $ psql -d postgres -U joe As the database administrator (shown here as "postgres"), check pg_log for a FATAL connection audit trail: $ sudo su - postgres $ cat ${PGDATA?}/pg_log/postgresql-Tue.log < 2016-02-16 16:18:13.027 EST joe 56c65135.b5f postgres: >LOG: connection authorized: user=joe database=postgres < 2016-02-16 16:18:13.027 EST 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.

Check Text ( C-73057r1_chk )

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

In this example the user joe will log into the Postgres database unsuccessfully:

$ psql -d postgres -U joe

As the database administrator (shown here as "postgres"), check pg_log for a FATAL connection audit trail:

$ sudo su - postgres
$ cat ${PGDATA?}/pg_log/postgresql-Tue.log
< 2016-02-16 16:18:13.027 EST joe 56c65135.b5f postgres: >LOG: connection authorized: user=joe database=postgres
< 2016-02-16 16:18:13.027 EST 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 (F-79367r2_fix)
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. To ensure that logging is enabled, review supplementary content APPENDIX-C for instructions on enabling logging. If logging is enabled the following configurations must be made to log unsuccessful connections, date/time, username, and session identifier. First, 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 Now, as the system administrator, reload the server with the new configuration: # SYSTEMD SERVER ONLY $ sudo systemctl reload postgresql-${PGVER?} # INITD SERVER ONLY $ sudo service postgresql-${PGVER?} reload

Fix Text (F-79367r2_fix)

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.

To ensure that logging is enabled, review supplementary content APPENDIX-C for instructions on enabling logging.

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

First, 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

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

# SYSTEMD SERVER ONLY
$ sudo systemctl reload postgresql-${PGVER?}

# INITD SERVER ONLY
$ sudo service postgresql-${PGVER?} reload