On January 8, Microsoft released security bulletin MS08-001, calling it critical but stressing that it would be “difficult and unlikely” to be exploited.

Immunity Inc. updated a working exploit on January 29 for the TCP/IP flaw, as spelled out in the January 8 bulletin, and posted a Flash demonstration of the attack on its Web site. The exploit has only been released to customers of Immunity’s CANVAS penetration testing software and is not available to the public.

From ComputerWorld:

“This demonstrates conclusively that the MS08-001 IGMPv3 vulnerability is highly exploitable,” said Dave Aitel, Immunity’s chief technology officer, in a message to his Dailydave security mailing list.

Aitel’s assertion challenged Microsoft’s earlier assessment that “there are a number of factors that make exploitation of this issue difficult and unlikely in real-world conditions.”

Immunity did acknowledge that its newest exploit was not 100% reliable, however.

Other security companies reacted to the revamped attack code and Flash proof by issuing new alerts. Symantec Corp., for instance, sent a new warning to customers of its DeepSight threat network. “The exploit demonstrates remote code execution,” noted Symantec. “The exploit works against Windows XP SP2 English Default [and shows] two Windows XP SP2 computers on a local subnet with firewall enabled being compromised.”

Also from ComputerWorld:

Successful attacks by the Immunity exploit — and any similar to it developed by others — allows arbitrary code to execute within the context of the Windows kernel, said Symantec, an especially egregious scenario for Windows Vista.

“This is especially critical on Vista, due to its enhanced kernel security mechanisms,” said Symantec. “A local user, even an admin, may have difficultly introducing unsigned code into the kernel, but in this case, it can be done remotely without any authentication whatsoever.

“This vulnerability presents an opportunity to not only execute arbitrary code on the system, but also to install backdoors and other malicious tools as well as a rootkit, which may normally be more difficult with a typical remote userland vulnerability.”

It is advised that if you have one of the versions of Windows that is impacted, you test and patch it immediately.

The intention here is not to raise the Windows security question or even the Vista security question. I wonder how many IT professionals get the security bulletins and take the Microsoft word as gospel when it rates a flaw. To be fair, Microsoft did rate this as “Critical” but appeared to soften the impact of that rating by stating that an exploit was “unlikely.” So, as a busy professional, how would you have read it, and what level of importance would you give it?

More information:

Microsoft Security Bulletin MS08-001


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