AIX must config the SSH idle timeout interval.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-91491	AIX7-00-002105	SV-101589r1_rule		Medium

Description
Automatic session termination addresses the termination of user-initiated logical sessions in contrast to the termination of network connections that are associated with communications sessions (i.e., network disconnect). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational information system. Such user sessions can be terminated (and thus terminate user access) without terminating network sessions. Session termination terminates all processes associated with a user's logical session except those processes that are specifically created by the user (i.e., session owner) to continue after the session is terminated. Conditions or trigger events requiring automatic session termination can include, for example, organization-defined periods of user inactivity, targeted responses to certain types of incidents, and time-of-day restrictions on information system use. This capability is typically reserved for specific operating system functionality where the system owner, data owner, or organization requires additional assurance.

Description

Automatic session termination addresses the termination of user-initiated logical sessions in contrast to the termination of network connections that are associated with communications sessions (i.e., network disconnect). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational information system. Such user sessions can be terminated (and thus terminate user access) without terminating network sessions. Session termination terminates all processes associated with a user's logical session except those processes that are specifically created by the user (i.e., session owner) to continue after the session is terminated. Conditions or trigger events requiring automatic session termination can include, for example, organization-defined periods of user inactivity, targeted responses to certain types of incidents, and time-of-day restrictions on information system use. This capability is typically reserved for specific operating system functionality where the system owner, data owner, or organization requires additional assurance.

STIG	Date
IBM AIX 7.x Security Technical Implementation Guide	2020-02-24

Details

Check Text ( C-90645r3_chk )
Run the following command to check if "ClientAliveInterval" and "ClientAliveCountMax" are set for SSH server: # grep -E "^ClientAliveInterval\|^ClientAliveCountMax" /etc/ssh/sshd_config ClientAliveInterval 300 ClientAliveCountMax 0 If "ClientAliveCountMax" is not set or its value is not "0", this is a finding. If "ClientAliveInterval" is not set, or its value is not "300" (5-minutes), this is a finding.

Check Text ( C-90645r3_chk )

Run the following command to check if "ClientAliveInterval" and "ClientAliveCountMax" are set for SSH server:

# grep -E "^ClientAliveInterval|^ClientAliveCountMax" /etc/ssh/sshd_config
ClientAliveInterval 300
ClientAliveCountMax 0

If "ClientAliveCountMax" is not set or its value is not "0", this is a finding.

If "ClientAliveInterval" is not set, or its value is not "300" (5-minutes), this is a finding.

Fix Text (F-97689r1_fix)
Add or update the following lines in "/etc/ssh/sshd_config": ClientAliveInterval 300 ClientAliveCountMax 0 Restart sshd: # stopsrc -s sshd # startsrc -s sshd