T1037.002

Description

Adversaries may use a Login Hook to establish persistence executed upon user logon. A login hook is a plist file that points to a specific script to execute with root privileges upon user logon.

The plist file is located in the <code>/Library/Preferences/com.apple.loginwindow.plist</code> file and can be modified using the <code>defaults</code> command-line utility. This behavior is the same for logout hooks where a script can be executed upon user logout.

All hooks require administrator permissions to modify or create hooks. Adversaries can add or insert a path to a malicious script in the <code>com.apple.loginwindow.plist</code> file, using the <code>LoginHook</code> or <code>LogoutHook</code> key-value pair.

The malicious script is executed upon the next user login. If a login hook already exists, adversaries can add additional commands to an existing login hook.

There can be only one login and logout hook on a system at a time. **Note:** Login hooks were deprecated in 10.11 version of macOS in favor of Launch Daemon and Launch Agent