Today we released Security Advisory 2914486 regarding a local elevation of privilege (EoP) issue that affects customers using Microsoft Windows XP and Server 2003. Windows Vista and later are not affected by this local EoP issue. A member of the Microsoft Active Protections Program (MAPP) found this issue being used on systems compromised by a third-party remote code execution vulnerability. These limited, targeted attacks require users to open a malicious PDF file. The issues described by the advisory cannot be used to gain access to a remote system alone.

While we are actively working to develop a security update to address this issue, we encourage customers running Windows XP and Server 2003 to deploy the following workarounds as described in the advisory:

Delete NDProxy.sys and reroute to Null.sys
For environments with non-default, limited user privileges, Microsoft has verified that the following workaround effectively blocks the attacks that have been observed in the wild.

We also always encourage people to follow the "Protect Your Computer" guidance of enabling a firewall, applying all software updates and installing anti-virus and anti-spyware software. We also encourage folks to exercise caution when visiting websites and avoid clicking suspicious links, or opening email messages from unfamiliar senders. Additional information can be found at www.microsoft.com/protect.

We hope this doesn’t disrupt any holiday plans you may have, but we did want to provide you with actionable information to help protect your systems. We continue to monitor the threat landscape closely and will take appropriate action to help protect customers.

Thank you,
Dustin Childs
Group Manager, Response Communications
Trustworthy Computing