Windows 7's malware infection rate climbs, XP's falls

But Windows 7 remains nearly five times less likely to get nailed by hackers, says Microsoft

Data released today by Microsoft showed that Windows 7's malware infection rate climbed by more than 30 per cent during the second half of 2010, even as the infection rate of the 10-year-old Windows XP fell by more than 20 per cent.

"Infection rates have jumped [for Windows 7]," admitted Jeff Williams, the principal group program manager with the Microsoft Malware Protection Center (MMPC). "We attribute that to the increased presence of malicious software attacks out there."

For the second half of 2010, 32-bit Windows 7 machines were infected at an average rate of over 4 PCs per 1,000, a 33 per cent increase over the approximately 3-per-1,000 infection rate during the first half of the year.

PCs running the 64-bit version of Windows 7 fared slightly better, with an infection rate of 2.5 per 1,000 during all of 2010.

The infection rates were tabulated from scans conducted by the Malicious Software Removal Tool (MSRT), a free utility updated monthly and pushed to Windows users via Microsoft's update services. MSFT detects and deletes selected malware, including fake antivirus programs, worms, viruses and bot Trojans.

Microsoft presented the newest infection numbers as part of its semi-annual security intelligence report, which it published today. The company normalized the data by comparing an equal number of computers for each edition of Windows.

Windows Vista Service Pack 2 (SP2), the latest edition of the problem- and perception-plagued OS, also experienced a jump in infection rates during the second half of 2010, the report noted.

In the second quarter, Vista SP2 was infected at a rate of about 6 machines per 1,000; that climbed to above 8 per 1,000 in the third quarter before slipping slightly in the fourth quarter.

Windows XP was the only one of Microsoft's three desktop editions to see its infection rate drop last year.

The infection rate of Windows XP SP3 -- the spring 2008 upgrade to the aged edition -- fell from a 2010 high of nearly 18 per 1,000 in the first quarter to just over 14 per 1,000 in the fourth quarter, a 22 per cent drop.

Windows XP's infection rate decline was responsible for the global drop that Microsoft charted last year. According to its data, the infection rate for all Windows machines fell from a high of 10.8 PCs per 1,000 in the first quarter to 8.7 per 1,000 in the fourth quarter.

But as Williams pointed out, Windows 7 and Vista are still much less likely to be compromised by malware than Windows XP. Windows XP SP3 had an average infection rate for all of 2010 of 15.9 machines per 1,000, almost five times Windows 7's and double that of Vista SP2's.

"We're still seeing a decrease [in infection rates] for the newer operating systems," said Williams. "And with the broader adoption of Windows 7, more customers are protected."

Microsoft has said it sold more than 350 million Windows 7 licenses since the edition debuted in October 2009.

Microsoft's latest security intelligence report can be downloaded from the company's Web site.

Windows 7's and Vista's infection rate climbed during 2010, but XP's fell.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed. His e-mail address is

Read more about security in Computerworld's Security Topic Center.

Join the CSO newsletter!

Error: Please check your email address.

Tags MicrosoftsecurityWindowssoftwareoperating systems

More about AppleMicrosoftMPCTopic

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Gregg Keizer

Latest Videos

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

  • 150x50

    IDG Live Webinar:The right collaboration strategy will help your business take flight

    Speakers - Mike Harris, Engineering Services Manager, Jetstar - Christopher Johnson, IT Director APAC, 20th Century Fox - Brent Maxwell, Director of Information Systems, THE ICONIC - IDG MC/Moderator Anthony Caruana

    Play Video

More videos

Blog Posts