SANS ISC: Yellow: MSIE VML exploit spreading

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SANS ISC InfoSec Forums

Yellow

The VML exploit is now becoming more widespread, so we changed the InfoCon level to yellow to emphasize the need to consider fixes.

If you have not taken measures yet, please consider some emergency fixes to cover the weekend (especially for those laptops surfing the web from home; they might be at high risk). The exploit is widely known, easy to recreate, and used in more and more mainstream websites.  The risk of getting hit is increasing significantly.

Outlook (including outlook 2003) is - as expected - also vulnerable and the email vector is being reported as exploited in the wild as well.

Weekends are moreover popular moments in time for the bad guys to build their botnets.

Actions

We suggest following actions (do them all: a layered approach will work when one of the measures fails):

• Update your antivirus software, make sure your vendor has protection for it.
• Unregister the vulnerable dll:

• Consider asking your users to stop their usage of MSIE, we know it's hard to break an addiction, but you're using the most targeted browser in the world.

Reregistering a DLL is done with the same command as unregistration, but without the "-u".

Quotes

Ken Dunham from iDefense claims they have seen a significant increase in attacks over the last 24 hours and "[at] least  one domain hosts provider has suffered a large-scale attack leading to index file modifications on over 500 domains". Those domains pointed visitors to a VML exploit. We're happy to note they join us in recommending "implementing a workaround ASAP" and see the upcoming weekend as a factor in it.

References

• US-CERT Vulnerability Note
• auscert Vulnerability Note (phishing like technique)
  
• Microsoft Security Advisory 925568
• Blocking VML using a GPO (use the magic incantations at own risk)
• Snort VRT
• Websense
• McAfee
• Symantec
• Trendmicro
• Panda
• F-secure
• xforce.iss
• Sept. 21st diary
• Sept. 19th diary

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Swa Frantzen -- Section66