APPL-26-000090 - The macOS system must disable login to other users' active and locked sessions.

Information

The ability to log in to another user's active or locked session must be disabled.

WARNING: This rule may cause issues when platformSSO is configured.

macOS has a privilege that can be granted to any user that will allow that user to unlock active users' sessions. Disabling the administrator's and/or user's ability to log in to another user's active and locked session prevents unauthorized people from viewing potentially sensitive and/or personal information.

Note: Configuring this setting will change the user experience and disable TouchID from unlocking the screen saver. To restore the user experience and allow TouchID to unlock the screen saver, run "/usr/bin/sudo /usr/bin/defaults write /Library/Preferences/com.apple.loginwindow screenUnlockMode -int 1". This setting can also be deployed with a configuration profile.

Satisfies: SRG-OS-000104-GPOS-00051, SRG-OS-000109-GPOS-00056

Solution

Configure the macOS system to disable login to other users' active and locked sessions with the following command:

SS_RULE=$(/usr/bin/security -q authorizationdb read system.login.screensaver 2>&1 | /usr/bin/xmllint --xpath "//dict/key[.='rule']/following-sibling::array[1]/string/text()" -)

if [[ "$SS_RULE" == *psso* ]]; then
/usr/bin/security -q authorizationdb read psso-screensaver > "/tmp/psso-screensaver-mscp.plist"
/usr/bin/sed -i.bak 's/<string>authenticate-session-owner-or-admin<\/string>/<string>authenticate-session-owner<\/string>/' /tmp/psso-screensaver-mscp.plist
/usr/bin/security -q authorizationdb write psso-screensaver-mscp < /tmp/psso-screensaver-mscp.plist
/usr/bin/security -q authorizationdb write system.login.screensaver psso-screensaver-mscp 2>&1
else
/usr/bin/security -q authorizationdb write system.login.screensaver "authenticate-session-owner" 2>&1
fi

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Apple_macOS_26_V1R1_STIG.zip

Item Details

Category: IDENTIFICATION AND AUTHENTICATION

References: 800-53|IA-2, CAT|II, CCI|CCI-000764, CCI|CCI-004045, Rule-ID|SV-277050r1149393_rule, STIG-ID|APPL-26-000090, Vuln-ID|V-277050

Plugin: Unix

Control ID: 9ab3c2976d5bc68504fa8ea7700daf89eccb02d660d4f514203d06a636912123