the exclamake! blog

Microsoft has released a statistical report on the results of the Malicious Software Removal Tool. The MSRT was released in January 2005 and has had mostly monthly updates since then. If you use Windows Update, Microsoft Update, or Automatic Updates, you most likely have this tool running on your computer.

It should be used in addition to your our desktop defenses because it does not scan for spyware and only scans for a subset of viruses deemed malicious. Also, it does not run in real-time, so cannot be relied on for comprehensive coverage.

The MSRT has been installed on 270 million computers in 24 languages, so gives a base to report on. The report brings out many statistical features and is a good read. It’s a long document, but some of the highlights I took note of:

• Backdoor trojans are the most popular malicious software, by far. 62% of infected computers contained at least one backdoor trojan. The most prevalent type of trojan was the bot, facilitator of the zombie networks.
• The rate of infected computers has been relatively constant at about .3%.
• Of the infected computers, the majority have not run the MSRT before. This is an interesting one to me because it highlights that it’s the newer computers that are more at risk. The interesting thing here is that there is a very small time delta between a new computer being put into service and the MSRT being downloaded by Automatic Updates. Malware’s getting in quickly.
• Windows SP2 is a necessity if you want to be protected better.

The full report can be found here in a Word document. Enjoy!