FYI...

Update on Zbot / MSRT removals
- https://blogs.technet.com/b/mmpc/arc...zbot-spot.aspx
31 Oct 2011 - "... prior to the September 2011 release, MSRT consistently detected about -90%- of PWS:Win32/Zbot variants in the wild. For the month of September 2011, we detected and removed PWS:Win32/Zbot from around 185,000 distinct Windows computers, a stark increase to the months beforehand... For October so far, we've removed Zbot from over 88,000 computers and we expect that number to grow to around 100,000... These increased numbers are also likely a result of new functionality we've seen in Zbot recently. It seems that some variants now automatically spread via the Windows autorun functionality; something that is very common with other prolific malware families, so it's not very surprising we're seeing it now - but is surprising we hadn't seen it before now. Regarding autorun, Microsoft released a security update in February of 2011* that changed its default behavior - the result was an overall decline in threats utilizing autorun as a spreading mechanism. There is a Microsoft Knowledge Base article that discusses how to disable autorun in Windows, here** ..."

* http://support.microsoft.com/kb/971029

** http://support.microsoft.com/kb/967715