PHTN-40-000203 The Photon operating system must terminate idle Secure Shell (SSH) sessions.

Information

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element.

Terminating network connections associated with communications sessions includes, for example, deallocating associated TCP/IP address/port pairs at the operating system level, and deallocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.

Solution

Navigate to and open:

/etc/ssh/sshd_config

Ensure the "ClientAliveCountMax" line is uncommented and set to the following:

ClientAliveCountMax 0

At the command line, run the following command:

# systemctl restart sshd.service

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_8-0_Y24M08_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-10, CAT|II, CCI|CCI-001133, Rule-ID|SV-258867r970703_rule, STIG-ID|PHTN-40-000203, Vuln-ID|V-258867

Plugin: Unix

Control ID: f588c5c32137906be6aa859d3dc22f2ac35f730675fe9d4d661e37cd4da6602e