Malware coders have already managed to bypass the initial antivirus signatures implemented with Security Update 2011-003, a report notes. A new version of Mac Defender, linked to a file called Mdinstall.pkg, appears to have been deliberately crafted to go undetected by up-to-date copies of Snow Leopard. The file is even timestamped to Tuesday at 9:24PM Pacific time, meaning that less than eight hours elapsed before attackers managed to once again circumvent Mac OS' protections.
