# Application Allowlisting

A security approach that only permits pre-approved software to run, blocking everything else by default.

**Application allowlisting[↗](/application-allowlisting)** (formerly called whitelisting) is a security approach that only permits explicitly pre-approved software to run on a system, blocking everything else by default, rather than trying to identify and block known-bad software after the fact.

This \"default deny\" model is highly effective against malware[↗](/malware), since unrecognized programs simply can't execute, but it requires more upfront management to keep the approved list current as legitimate software changes and updates.