ALERT: Please install critical out-of-band security patch
Edit: A detailed description of the vulnerability has been published here:
Of particular importance is this quote:
"This is a serious vulnerability and we have seen targeted attacks using this vulnerability to compromise fully-patched Windows XP and Windows Server 2003 computers so we have released the fix "out of band" (not on the regular Patch Tuesday)."
We're all patched - I strongly recommend you ensure all of your computers are patched too.
"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.
This security update is rated Critical for all supported editions of Microsoft Windows 2000, Windows XP, Windows Server 2003, and rated Important for all supported editions of Windows Vista and Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerability by correcting the way that the Server service handles RPC requests. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
Recommendation. Microsoft recommends that customers apply the update immediately.
Known Issues. None"
Note that even the Windows 7 Pre-Release beta is affected, although it should be noted that only authenticated users are affected.
- Firewall best practices and standard default firewall configurations can help protect network resources from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.
- On Windows Vista and Windows Server 2008, the vulnerable code path is only accessible to authenticated users. This vulnerability is not liable to be triggered if the attacker is not authenticated.