AppLocker is a Windows application control feature that restricts which apps, scripts, DLLs, and installers can run based on administrator-defined rules. Rules can target a file’s publisher, path, or hash, letting defenders approve trusted software while blocking everything else by default.
In cyber security, AppLocker helps reduce unauthorized execution, which is a common step in malware delivery, ransomware deployment, and post-exploitation persistence. If an attacker drops a payload, launches a script, or tries to run a risky installer from a user-writable location, a strong policy can stop it before execution. Defenders often use AppLocker alongside least privilege, software inventory, and audit mode during rollout so legitimate business tools are not blocked. It is effective, but only when policies are maintained as software changes.