Vulnerabilities in Internet Authentication Service

This security update resolves two privately reported vulnerabilities in Microsoft Windows. The more severe of these vulnerabilities could allow remote code execution if messages received by the Internet Authentication Service server are copied incorrectly into memory when handling PEAP authentication attempts. On Windows Server 2008, the Internet Authentication Service is replaced by Network Policy Server (NPS). An attacker who successfully exploited either of these vulnerabilities could take complete control of an affected system. Servers using Internet Authentication Service or Network Policy Server are only affected when using PEAP with MS-CHAP v2 authentication.

This security update is rated Critical for Windows Server 2008 for 32-bit Systems Service Pack 2 and Windows Server 2008 for x64-based Systems Service Pack 2. For all other affected and supported releases of Windows, see the subsection, Affected and Non-Affected Software, in this section.

See:
http://support.microsoft.com/kb/974318/en-us
http://www.microsoft.com/technet/security/Bulletin/MS09-071.mspx