PostgreSQL must be configurable to overwrite audit log records, oldest first (First-In-First-Out [FIFO]), in the event of unavailability of space for more audit log records.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-233536	CD12-00-002800	SV-233536r617333_rule		Low

Description
It is critical that when PostgreSQL is at risk of failing to process audit logs as required, it take action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When availability is an overriding concern, approved actions in response to an audit failure are as follows: (i) If the failure was caused by the lack of audit record storage capacity, PostgreSQL must continue generating audit records, and if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. (ii) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, PostgreSQL must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server. Systems where availability is paramount will most likely be MAC I; the final determination is the prerogative of the application owner, subject to Authorizing Official concurrence. Sufficient auditing resources must be allocated to avoid audit data loss in all but the most extreme situations.

Description

It is critical that when PostgreSQL is at risk of failing to process audit logs as required, it take action to mitigate the failure. Audit processing failures include software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When availability is an overriding concern, approved actions in response to an audit failure are as follows: (i) If the failure was caused by the lack of audit record storage capacity, PostgreSQL must continue generating audit records, and if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. (ii) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, PostgreSQL must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server. Systems where availability is paramount will most likely be MAC I; the final determination is the prerogative of the application owner, subject to Authorizing Official concurrence. Sufficient auditing resources must be allocated to avoid audit data loss in all but the most extreme situations.

STIG	Date
Crunchy Data PostgreSQL Security Technical Implementation Guide	2020-12-11

Details

Check Text ( C-36730r606831_chk )
If the AO approved system documentation states that system availability takes precedence, this requirement is not applicable (NA). If an externally managed and monitored partition or logical volume that can be grown dynamically is being used for logging, this is not a finding. If PostgreSQL is auditing to a directory that is not being actively checked for availability of disk space, and if a tool, utility, script, or other mechanism is not being used to ensure sufficient disk space is available for the creation of new audit logs, this is a finding. If a tool, utility, script, or other mechanism is being used to rotate audit logs, and oldest logs are not being removed to ensure sufficient space for newest logs, or oldest logs are not being replaced by newest logs, this is a finding.

Check Text ( C-36730r606831_chk )

If the AO approved system documentation states that system availability takes precedence, this requirement is not applicable (NA).

If an externally managed and monitored partition or logical volume that can be grown dynamically is being used for logging, this is not a finding.

If PostgreSQL is auditing to a directory that is not being actively checked for availability of disk space, and if a tool, utility, script, or other mechanism is not being used to ensure sufficient disk space is available for the creation of new audit logs, this is a finding.

If a tool, utility, script, or other mechanism is being used to rotate audit logs, and oldest logs are not being removed to ensure sufficient space for newest logs, or oldest logs are not being replaced by newest logs, this is a finding.

Fix Text (F-36695r606832_fix)
Establish a process with accompanying tools for monitoring available disk space and ensuring that sufficient disk space is maintained in order to continue generating audit logs, overwriting the oldest existing records if necessary.