Microsoft updated Security Advisory (951306) last week. A vulnerability exists from last April that allowed local privilege escalation. The update to the advisory was made since there is now exploit code online. There is currently no patch available but a workaround is possible:
Microsoft is investigating new public reports of a vulnerability which could allow elevation of privilege from authenticated user to LocalSystem, affecting Windows XP Professional Service Pack 2, Windows XP Professional Service Pack 3, and all supported versions and editions of Windows Server 2003, Windows Vista, and Windows Server 2008. Customers who allow user-provided code to run in an authenticated context, such as within Internet Information Services (IIS) and SQL Server, should review this advisory. Hosting providers may be at increased risk from this elevation of privilege vulnerability.
Microsoft is aware that exploit code has been published on the Internet for the vulnerability addressed by this advisory. Our investigation of this exploit code has verified that it does not affect customers who have applied the workarounds listed below on their computers. Currently, Microsoft is not aware of active attacks that use this exploit code or of customer impact at this time. However, Microsoft is actively monitoring this situation to keep customers informed and to provide customer guidance as necessary. Upon completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a solution through a service pack, our monthly security update release process, or an out-of-cycle security update, depending on customer needs.
(Source: Microsoft Technet)
Check the Advisory for more information.
