Microsoft has released security bulletin MS08-067, Vulnerability in Server Service Could Allow Remote Code Execution (958644), to address a vulnerability in all currently supported versions of Windows. This security update was released outside of the usual monthly security bulletin release cycle in an effort to protect customers. This is the first out-of-band critical update since April 2007.
This security update resolves a privately reported vulnerability in the Server service. The vulnerability could allow remote code execution if an affected system received a specially crafted RPC request. On Microsoft Windows 2000, Windows XP, and Windows Server 2003 systems, an attacker could exploit this vulnerability without authentication to run arbitrary code. It is possible that this vulnerability could be used in the crafting of a wormable exploit. Firewall best practices and standard default firewall configurations can help protect network resources from attacks that originate outside the enterprise perimeter. The security update addresses the vulnerability by correcting the way that the Server service handles RPC requests.
Recommendation. Microsoft recommends that customers apply the update immediately.
Update 28th October 2008:
On Monday 27th October Microsoft released a Security Advisory 958963 – Exploit Code Published Affecting the Server Service.
Microsoft is aware that detailed exploit code demonstrating code execution has been published on the Internet for the vulnerability that is addressed by security update MS08-067. This exploit code demonstrates code execution on Windows 2000, Windows XP, and Windows Server 2003. Microsoft is aware of limited, targeted active attacks that use this exploit code. At this time, there are no self-replicating attacks associated with this vulnerability. Microsoft has activated its Software Security Incident Response Process (SSIRP) and is continuing to investigate this issue.
Our investigation of this exploit code has verified that it does not affect customers who have installed the updates detailed in MS08-067 on their computers. Microsoft continues to recommend that customers apply the updates to the affected products by enabling the Automatic Updates feature in Windows.
- Microsoft TechNet Security Site: Bulletin MS08-067
- Microsoft Security Response Center (MSRC) Blog: MS08-067 Further Guidance
- Microsoft Security Vulnerability Research and Defense (SVRD) Blog: MS08-068 Technical Detail