It's been a while since we've done a good top malware threats list here, but a new list just came out from Microsoft based on their MSRT, or Malicious Software Removal Tool. This is a tool that runs every month at Patch Tuesday time, so it has very broad, worldwide reach. The downside to it is that it searches for and removes a list of malware that is small compared to that of a real anti-malware product (well, it's a lot bigger than Apple's list, but Microsoft has a bigger problem and perhaps we should give Apple some time).


The top 10 threats removed by the tool:
Family Threat Count Machine Count
Taterf 544,662 463,000
Renos 308,789 228,973
Alureon 249,101 211,441
FakeRean 219,359 162,328
Bancos 173,134 158,152
Koobface 274,769 134,139
Frethog 140,218 132,827
Cutwail 166,284 110,840
Rustock 98,673 90,788
Tibs 93,175 84,081



Off the top of my head I only recognize the names Koobface, Bancos and Renos. Koobface is clearly a major threat, but it gets a lot of attention because its Facebook association makes it a sexy story. How many of you have heard of Taterf? Microsoft's definition of it describes it as "...a family of worms that spread via mapped drives in order to steal login and account details for popular online games." CA's description indicates that other vendors, including Symantec and McAfee, use a generic "Trojan" moniker, which perhaps explains the Taterf name's anonymity.

The top 10 threats were cleaned from a total of 1,776,569 machines. The country data below makes clear that there are a lot of machines not in the top 10 list.

Country/Region Threat Count Machine Count
US 8,750,628 2,183,166
China 1,085,140 383,378
Brazil 737,322 282,152
UK 1,078,540 278,207
Korea 601,646 262,539
France 412,115 156,566
Taiwan 236,047 140,283
Spain 328,829 133,264
Canada 433,770 119,885
Mexico 447,841 117,845

http://blogs.technet.com/mmpc/archive/2009...on-reports.aspx
http://blogs.pcmag.com/securitywatch/2009/..._10_windows.php