The SSH daemon ClientAliveCountMax option must be set correctly.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-51351	OSX8-00-00720	SV-65561r1_rule		Medium

Description
This requirement applies to both internal and external networks. Terminating network connections associated with communications sessions means de-allocating associated TCP/IP address/port pairs at the operating system level. The time period of inactivity may, as the organization deems necessary, be a set of time periods by type of network access or for specific accesses.

STIG	Date
Apple OS X 10.8 (Mountain Lion) Workstation STIG	2015-02-10

Details

Check Text ( C-53695r1_chk )
To ensure the SSH idle timeout will occur when the "ClientAliveCountMax" is set, run the following command: grep ClientAliveCountMax /etc/sshd_config If the setting is commented out, or not "ClientAliveCountMax 0", this is a finding.

Fix Text (F-56151r1_fix)
In order to make sure that the SSH idle timeout occurs precisely when the "ClientAliveCountMax" is set, run the following command: sudo sed -i.bak 's/.*ClientAliveCountMax.*/ClientAliveCountMax 0/' /etc/sshd_config .