Apple has released Security Update 2011-003, a patch for Mac OS X Snow Leopard. The fix’s main goal is protection against Mac Defender, a piece of malware that attempts to scam credit card numbers from people duped into installing it. A definition for Mac Defender has been added to File Quarantine, and when the code is detected Snow Leopard will try to remove it. The new safeguards cover both Mac Defender itself and unspecified variants.
The update also makes a quiet but significant change to Snow Leopard’s behavior. The OS will now automatically update malware definitions, a practice common amongst third-party antivirus scanners, or Microsoft’s first-party Security Essentials in the case of Windows. Mac owners can opt out of automatic updates by toggling “Automatically update safe downloads list” under Security Preferences.
