What is Whitelisting?

Understanding Whitelisting

The reverse of blacklisting where everything is denied by default and only allowed items on the whitelist are permitted. Whitelisting also called allowlisting is a security approach that denies everything by default and only permits explicitly approved applications files processes or entities to execute run or connect. This restrictive approach offers stronger security than blacklisting by preventing unknown threats and zero-day attacks. Allowlisting is recommended in standards like NIST SP 800-167 CIS Controls and various security frameworks. Organizations implement whitelisting through application control solutions software restriction policies trusted publisher configurations and executable control mechanisms. For example a critical infrastructure organization might implement comprehensive application whitelisting where only specifically approved executables can run on operational technology systems hash-based verification ensures software integrity publisher-based rules allow updates only from trusted vendors change control processes govern modifications to the whitelist and monitoring systems alert on any attempted violations of the whitelist policy creating a highly restrictive but secure environment. Related terms Application control Application whitelisting Allowlisting Software restriction policies Default deny Trusted applications Publisher whitelisting Hash-based allowlisting Zero trust Application security.