The macOS system must configure SSH ServerAliveInterval option set to 900.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-259445 | APPL-14-000110 | SV-259445r970703_rule | CCI-001133 | medium |
| Description | ||||
| SSH must be configured with an Active Server Alive Maximum Count set to 900. Setting the Active Server Alive Maximum Count to 900 will log users out after a 900-second interval of inactivity. Note: /etc/ssh/ssh_config will be automatically modified to its original state following any update or major upgrade to the operating system. | ||||
| STIG | Date | |||
| Apple macOS 14 (Sonoma) Security Technical Implementation Guide | 2024-12-04 | |||
Details
Check Text (C-259445r970703_chk)
Verify the macOS system is configured to set the SSH ServerAliveInterval option set to 900 with the following command:
ret="pass"
for u in $(/usr/bin/dscl . -list /Users UniqueID | /usr/bin/awk '$2 > 500 {print $1}'); do
sshCheck=$(/usr/bin/sudo -u $u /usr/bin/ssh -G . | /usr/bin/grep -c "^serveraliveinterval 900")
if [[ "$sshCheck" == "0" ]]; then
ret="fail"
break
fi
done
/bin/echo $ret
If the result is not "pass", this is a finding.
Fix Text (F-63092r940956_fix)
Configure the macOS system to set the SSH ServerAliveInterval option set to 900 with the following command:
for u in $(/usr/bin/dscl . -list /Users UniqueID | /usr/bin/awk '$2 > 500 {print $1}'); do
config=$(/usr/bin/sudo -u $u /usr/bin/ssh -Gv . 2>&1 | /usr/bin/awk '/Reading configuration data/ {print $NF}'| /usr/bin/tr -d '\r')
configarray=( ${(f)config} )
for c in $configarray; do
/usr/bin/sudo -u $u /usr/bin/grep -q '^ServerAliveInterval' "$c" && /usr/bin/sed -i '' 's/.*ServerAliveInterval.*/ServerAliveInterval 900/' "$c" || /bin/echo 'ServerAliveInterval 900' >> "$c"
done
done