Whitelisting

Whitelisting (also called allowlisting) is a security approach where only specifically approved items — applications, email addresses, IP addresses, or websites — are permitted, and everything else is blocked by default. This is the opposite of blacklisting, where known bad items are blocked but everything else is allowed.

Application whitelisting is particularly effective against malware because only pre-approved software can run on a system. Even if an attacker manages to place malware on the system, it can't execute because it's not on the approved list. This provides strong protection against zero-day threats that antivirus might not detect.