PostgreSQL must generate audit records when unsuccessful accesses to objects occur.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72951	PGS9-00-005700	SV-87603r1_rule		Medium

Description
Without tracking all or selected types of access to all or selected objects (tables, views, procedures, functions, etc.), it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. In an SQL environment, types of access include, but are not necessarily limited to: SELECT INSERT UPDATE DROP EXECUTE To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Description

Without tracking all or selected types of access to all or selected objects (tables, views, procedures, functions, etc.), it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. In an SQL environment, types of access include, but are not necessarily limited to: SELECT INSERT UPDATE DROP EXECUTE To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

STIG	Date
PostgreSQL 9.x Security Technical Implementation Guide	2018-02-27

Details

Check Text ( C-73081r1_chk )
Note: The following instructions use the PGDATA environment variable. See supplementary content APPENDIX-F for instructions on configuring PGDATA. First, as the database administrator (shown here as "postgres"), create a schema, test_schema, create a table, test_table, within test_schema, and insert a value: $ sudo su - postgres $ psql -c "CREATE SCHEMA test_schema" $ psql -c "CREATE TABLE test_schema.test_table(id INT)" $ psql -c "INSERT INTO test_schema.test_table(id) VALUES (0)" Next, create a role 'bob' and attempt to SELECT, INSERT, UPDATE, and DROP from the test table: $ psql -c "CREATE ROLE BOB" $ psql -c "SELECT * FROM test_schema.test_table" $ psql -c "INSERT INTO test_schema.test_table VALUES (0)" $ psql -c "UPDATE test_schema.test_table SET id = 1 WHERE id = 0" $ psql -c "DROP TABLE test_schema.test_table" $ psql -c "DROP SCHEMA test_schema" Now, as the database administrator (shown here as "postgres"), review PostgreSQL/database security and audit settings to verify that audit records are created for unsuccessful attempts at the specified access to the specified objects: $ sudo su - postgres $ cat ${PGDATA?}/pg_log/ 2016-03-30 17:23:41.254 EDT postgres postgres ERROR: permission denied for schema test_schema at character 15 2016-03-30 17:23:41.254 EDT postgres postgres STATEMENT: SELECT * FROM test_schema.test_table; 2016-03-30 17:23:53.973 EDT postgres postgres ERROR: permission denied for schema test_schema at character 13 2016-03-30 17:23:53.973 EDT postgres postgres STATEMENT: INSERT INTO test_schema.test_table VALUES (0); 2016-03-30 17:24:32.647 EDT postgres postgres ERROR: permission denied for schema test_schema at character 8 2016-03-30 17:24:32.647 EDT postgres postgres STATEMENT: UPDATE test_schema.test_table SET id = 1 WHERE id = 0; 2016-03-30 17:24:46.197 EDT postgres postgres ERROR: permission denied for schema test_schema 2016-03-30 17:24:46.197 EDT postgres postgres STATEMENT: DROP TABLE test_schema.test_table; 2016-03-30 17:24:51.582 EDT postgres postgres ERROR: must be owner of schema test_schema 2016-03-30 17:24:51.582 EDT postgres postgres STATEMENT: DROP SCHEMA test_schema; If any of the above steps did not create audit records for SELECT, INSERT, UPDATE, and DROP, this is a finding.

Check Text ( C-73081r1_chk )

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

First, as the database administrator (shown here as "postgres"), create a schema, test_schema, create a table, test_table, within test_schema, and insert a value:

$ sudo su - postgres
$ psql -c "CREATE SCHEMA test_schema"
$ psql -c "CREATE TABLE test_schema.test_table(id INT)"
$ psql -c "INSERT INTO test_schema.test_table(id) VALUES (0)"

Next, create a role 'bob' and attempt to SELECT, INSERT, UPDATE, and DROP from the test table:

$ psql -c "CREATE ROLE BOB"
$ psql -c "SELECT * FROM test_schema.test_table"
$ psql -c "INSERT INTO test_schema.test_table VALUES (0)"
$ psql -c "UPDATE test_schema.test_table SET id = 1 WHERE id = 0"
$ psql -c "DROP TABLE test_schema.test_table"
$ psql -c "DROP SCHEMA test_schema"

Now, as the database administrator (shown here as "postgres"), review PostgreSQL/database security and audit settings to verify that audit records are created for unsuccessful attempts at the specified access to the specified objects:

$ sudo su - postgres
$ cat ${PGDATA?}/pg_log/
2016-03-30 17:23:41.254 EDT postgres postgres ERROR: permission denied for schema test_schema at character 15
2016-03-30 17:23:41.254 EDT postgres postgres STATEMENT: SELECT * FROM test_schema.test_table;
2016-03-30 17:23:53.973 EDT postgres postgres ERROR: permission denied for schema test_schema at character 13
2016-03-30 17:23:53.973 EDT postgres postgres STATEMENT: INSERT INTO test_schema.test_table VALUES (0);
2016-03-30 17:24:32.647 EDT postgres postgres ERROR: permission denied for schema test_schema at character 8
2016-03-30 17:24:32.647 EDT postgres postgres STATEMENT: UPDATE test_schema.test_table SET id = 1 WHERE id = 0;
2016-03-30 17:24:46.197 EDT postgres postgres ERROR: permission denied for schema test_schema
2016-03-30 17:24:46.197 EDT postgres postgres STATEMENT: DROP TABLE test_schema.test_table;
2016-03-30 17:24:51.582 EDT postgres postgres ERROR: must be owner of schema test_schema
2016-03-30 17:24:51.582 EDT postgres postgres STATEMENT: DROP SCHEMA test_schema;

If any of the above steps did not create audit records for SELECT, INSERT, UPDATE, and DROP, this is a finding.

Fix Text (F-79397r1_fix)
Configure PostgreSQL to produce audit records when unsuccessful attempts to access objects occur. All errors and denials are logged if logging is enabled. To ensure that logging is enabled, review supplementary content APPENDIX-C for instructions on enabling logging.