Mac security company Intego has taken a closer look at the limitations of Apple's new anti-malware features in the recent Snow Leopard update. The new security functions, noticed by developers shortly before the public release, alert users to malicious code found in downloaded files.

Although Apple's malware detection codes flag certain downloads from the Internet, the operating system still allows local file transfers to be completed without scanning the data. The system also ignores any meta-package files, even if they might contain viruses.

The integrated Snow Leopard protection allegedly looks for just two Trojan viruses, despite the wider range of known threats, while certain variations of the most popular Trojans also slip through without any problem. In its current form, the features are limited to preventative detection and offer no solution for infected Macs.

As Mac OS X security features are still in the beginning stages of development, Apple did not boast of a comprehensive anti-malware system when the OS update was introduced. It remains unknown if the company plans to expand the capabilities and scope of the integrated anti-virus functionality. In the meantime, the most complete protection is available through third-party software.

Graham Cluley of Sophos claims Apple took a step backward with Snow Leopard security, despite the virus scanner. The OS update reportedly downgrades Adobe Flash to an earlier version, leaving the system vulnerable to a variety of threats that have already been patched with the latest release.

"Mac users who have been diligent enough to keep their security up-to-date do not deserve to be silently downgraded," Cluley wrote on his blog. Users can visit Adobe's dedicated test site to view their Flash version.