When invalid inputs are received, PostgreSQL must behave in a predictable and documented manner that reflects organizational and system objectives.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-261934	CD16-00-009000	SV-261934r1000807_rule		Medium

Description
A common vulnerability is unplanned behavior when invalid inputs are received. This requirement guards against adverse or unintended system behavior caused by invalid inputs, where information system responses to the invalid input may be disruptive or cause the system to fail into an unsafe state. The behavior will be derived from the organizational and system requirements and includes, but is not limited to, notification of the appropriate personnel, creating an audit record, and rejecting invalid input. This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

Description

A common vulnerability is unplanned behavior when invalid inputs are received. This requirement guards against adverse or unintended system behavior caused by invalid inputs, where information system responses to the invalid input may be disruptive or cause the system to fail into an unsafe state. The behavior will be derived from the organizational and system requirements and includes, but is not limited to, notification of the appropriate personnel, creating an audit record, and rejecting invalid input. This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

STIG	Date
Crunchy Data Postgres 16 Security Technical Implementation Guide	2024-06-17

Details

Check Text ( C-65788r1000805_chk )
Review system documentation to determine how input errors from application to PostgreSQL are to be handled in general and if any special handling is defined for specific circumstances. If it does not implement the documented behavior, this is a finding. As the database administrator (shown here as "postgres"), make a small SQL syntax error in psql by running the following: $ sudo su - postgres $ psql -c "CREAT TABLE incorrect_syntax(id INT)" ERROR: syntax error at or near "CREAT" Note: The following instructions use the PGVER and PGLOG environment variables. Refer to supplementary content APPENDIX-H for instructions on configuring PGVER and APPENDIX-I for PGLOG. As the database administrator (shown here as "postgres"), verify the syntax error was logged (change the log file name and part to suit the circumstances): $ sudo su - postgres $ cat ~/${PGVER?}/data/${PGLOG?}/ 2024-03-30 16:18:10.772 EDT postgres postgres 5706bb87.90dERROR: syntax error at or near "CREAT" at character 1 2024-03-30 16:18:10.772 EDT postgres postgres 5706bb87.90dSTATEMENT: CREAT TABLE incorrect_syntax(id INT); If no matching log entry containing the 'ERROR: syntax error' is present, this is a finding.

Check Text ( C-65788r1000805_chk )

Review system documentation to determine how input errors from application to PostgreSQL are to be handled in general and if any special handling is defined for specific circumstances.

If it does not implement the documented behavior, this is a finding.

As the database administrator (shown here as "postgres"), make a small SQL syntax error in psql by running the following:

$ sudo su - postgres
$ psql -c "CREAT TABLE incorrect_syntax(id INT)"
ERROR: syntax error at or near "CREAT"

Note: The following instructions use the PGVER and PGLOG environment variables. Refer to supplementary content APPENDIX-H for instructions on configuring PGVER and APPENDIX-I for PGLOG.

As the database administrator (shown here as "postgres"), verify the syntax error was logged (change the log file name and part to suit the circumstances):

$ sudo su - postgres
$ cat ~/${PGVER?}/data/${PGLOG?}/
2024-03-30 16:18:10.772 EDT postgres postgres 5706bb87.90dERROR: syntax error at or near "CREAT" at character 1
2024-03-30 16:18:10.772 EDT postgres postgres 5706bb87.90dSTATEMENT: CREAT TABLE incorrect_syntax(id INT);

If no matching log entry containing the 'ERROR: syntax error' is present, this is a finding.

Fix Text (F-65696r1000806_fix)
Enable logging. To ensure logging is enabled, see the instructions in the supplementary content APPENDIX-C. All errors and denials are logged if logging is enabled.