PGS9-00-001200 - PostgreSQL must limit the number of concurrent sessions to an organization-defined number per user for all accounts and/or account types.

Information

Database management includes the ability to control the number of users and user sessions utilizing PostgreSQL. Unlimited concurrent connections to PostgreSQL could allow a successful Denial of Service (DoS) attack by exhausting connection resources; and a system can also fail or be degraded by an overload of legitimate users. Limiting the number of concurrent sessions per user is helpful in reducing these risks.

This requirement addresses concurrent session control for a single account. It does not address concurrent sessions by a single user via multiple system accounts; and it does not deal with the total number of sessions across all accounts.

The capability to limit the number of concurrent sessions per user must be configured in or added to PostgreSQL (for example, by use of a logon trigger), when this is technically feasible. Note that it is not sufficient to limit sessions via a web server or application server alone, because legitimate users and adversaries can potentially connect to PostgreSQL by other means.

The organization will need to define the maximum number of concurrent sessions by account type, by account, or a combination thereof. In deciding on the appropriate number, it is important to consider the work requirements of the various types of users. For example, 2 might be an acceptable limit for general users accessing the database via an application; but 10 might be too few for a database administrator using a database management GUI tool, where each query tab and navigation pane may count as a separate session.

(Sessions may also be referred to as connections or logons, which for the purposes of this requirement are synonyms.)

Solution

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 configure the maximum amount of connections allowed to the database, as the database administrator (shown here as 'postgres') change the following in postgresql.conf (the value 10 is an example; set the value to suit local conditions):

$ sudo su - postgres
$ vi ${PGDATA?}/postgresql.conf
max_connections = 10

Next, restart the database:

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

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

To limit the amount of connections allowed by a specific role, as the database administrator, run the following SQL:

$ psql -c 'ALTER ROLE <rolname> CONNECTION LIMIT 1';

Item Details

Audit Name: DISA STIG PostgreSQL 9.x on RHEL DB v2r5

Category: ACCESS CONTROL

Plugin: PostgreSQLDB

Control ID: 60c4d2df57c4838cc19d5f09d19994c7d4b877594b013c9aa53327a2ecbc80aa

Detections

Analytics

PGS9-00-001200 - PostgreSQL must limit the number of concurrent sessions to an organization-defined number per user for all accounts and/or account types.

Information

Solution

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Item Details