Threat Level: green Handler on Duty: Brad Duncan

SANS ISC: InfoSec Handlers Diary Blog - * Microsoft Patches Released InfoSec Handlers Diary Blog


Sign Up for Free!   Forgot Password?
Log In or Sign Up for Free!

* Microsoft Patches Released

Published: 2006-01-06
Last Updated: 2006-01-06 19:25:45 UTC
by Marcus Sachs (Version: 4)
0 comment(s)
Many of you already know this if you receive advance notification from Microsoft.  For everybody else, see their announcement about an early release of the WMF patch.  The patch and details about it are available here.  If you have installed any of the earlier patches or workarounds, here is our recommendation for updating:

1.  Reboot your system to clear any vulnerable files from memory
2.  Download and apply the new patch
3.  Reboot
4.  Uninstall the unofficial patch, by using one of these methods:
a.  Add/Remove Programs on single systems.  Look for "Windows WMF Metafile Vulnerability HotFix"
b. or at a command prompt:
"C:\Program Files\WindowsMetafileFix\unins000.exe" /SILENT
c. or, if you used msi to install the patch on multiple machines you can uninstall it with this:
msiexec.exe /X{E1CDC5B0-7AFB-11DA-8CD6-0800200C9A66} /qn
5.  Re-register the .dll if you previously unregistered it (use the same command but without the "-u"):
regsvr32 %windir%\system32\shimgvw.dll
6.  Optionally, reboot one more time just for good measure (not required, but doesn't hurt)

We tested the patch, and it does block the attack just like the unofficial patch does.

If you experience any problems with the official patch, check support.microsoft.com and call the toll-free number listed for free assistance. Microsoft will not support the unofficial patch. As an alternative to the sequence shown above, you may want to uninstall the unofficial patch first. But make sure you keep shimgvw.dll unregistered until the official patch is applied. Either sequence works in our testing. Removing the unofficial patch later provides an extra layer of protection.

You can use our test image at http://sipr . net/test . wmf as a test to make sure you are not vulnerable. The test image will start the calculator if you are vulnerable.

I'd like to take this opportunity to thank all of our incident handlers for the endless hours of analysis over the past week.  Also, many thanks to the hundreds of readers who sent in analysis and observations.  Finally, thanks to the response team at Microsoft for issuing the patch today.  We all appreciate the extra internal effort it took to do this out of cycle.

Marcus  H. Sachs
Director, SANS Internet Storm Center

UPDATED News on the official WMF patch and DLL registration

  • If you installed the LEAKED Microsoft patch, make sure that you un-install it before installing the officially released patch. Windows Update will detect the presence of the leaked patch. Bad things may happen.

  • If you installed the un-official Ilfak patch, you can un-install it before or after the official Microsoft patch. The order doesn't matter, should work either way. Windows Update will apparently not detect the un-official patch.

  • If you un-registered the DLL (shimgvw.dll) you will need to re-register it in order to regain the functionality. The official Microsoft patch will NOT re-register the DLL for you. You will have to do it via the followng command:
                regsvr32 %windir%\\system32\\shimgvw.dll

  • ISC has pulled the un-official patch from our web site, if you download the text file that replaces it, it won't execute.






Keywords:
0 comment(s)
Diary Archives