STIGQter: STIG Summary: Riverbed NetIM OS Security Technical Implementation Guide Version: 1 Release: 1 Benchmark Date: 11 Sep 2025:

Ubuntu OS must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive.

DISA Rule

SV-275621r1147913_rule

Vulnerability Number

V-275621

Group Title

SRG-OS-000163-GPOS-00072

Rule Version

RIIM-OS-255030

Severity

CAT II

CCI(s)

• CCI-001133 - Terminate the network connection associated with a communications session at the end of the session or after an organization-defined time period of inactivity.

Weight

10

Fix Recommendation

Configure the SSH server to terminate a user session automatically after the SSH client has been unresponsive for 10 minutes.

Note: This setting must be applied in conjunction with RIIM-OS-255040 to function correctly.

Add or modify the following line in the "/etc/ssh/sshd_config" file:

ClientAliveInterval 600

Restart the SSH daemon for the changes to take effect:

$ sudo systemctl restart sshd.service

Check Contents

Verify the SSH server automatically terminates a user session after the SSH client has been unresponsive for 10 minutes by using the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'clientaliveinterval'
/etc/ssh/sshd_config:ClientAliveInterval 600

If "ClientAliveInterval" does not exist, is not set to a value of "600" or less, if conflicting results are returned, is commented out, or is missing, this is a finding.

Vulnerability Number

V-275621

Documentable

False

Rule Version

RIIM-OS-255030

Severity Override Guidance

Verify the SSH server automatically terminates a user session after the SSH client has been unresponsive for 10 minutes by using the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'clientaliveinterval'
/etc/ssh/sshd_config:ClientAliveInterval 600

If "ClientAliveInterval" does not exist, is not set to a value of "600" or less, if conflicting results are returned, is commented out, or is missing, this is a finding.

Check Content Reference

M

Target Key

5706