Symantec has reported a number of vulnerabilities in Windows Vista in its third report on the new OS. Although the two companies are partners, Symantec is now in direct competition with Microsoft following the latter's move into the anti-virus space.

Matthew Conover, principal security researcher at Symantec, said in the report that although the overall security of the OS kernel has increased dramatically over XP, "we have identified certain weaknesses in the kernel enhancements that may be leveraged by malicious code to undermine these improvements".

Conover claims the PatchGuard feature, which checks the integrity of key parts of the kernel code, can be disabled. His other concern is that attackers could force dangerous unsigned driver software to run by patching core OS files. The same feature has already been attacked by security researchers at Black Hat.

Microsoft says the report, "Assessment of Windows Vista Kernel-Mode Security", which focuses on build 5365 of Vista, a 64-bit version released in April, is old news, as most of the issues have been dealt with in later versions. Vista is the company's successor OS to XP, and is set to go on general release in January.