Microsoft Report Confirms Lower Infection Rate On Windows 7

Martin Brinkmann
May 14, 2011
Updated • Dec 15, 2014

If you were looking for a reason to make the switch to Windows 7, you may have found it in form of Microsoft's latest Security Intelligence Report. The document, available for public download at Microsoft's Security Intelligence Report website, covers the state of Windows, application and web security in the year 2010.

Security interested users find lots of information in the report, including the most dominant threats and trends.

You will find information about infection rates for Microsoft operating systems somewhere in the middle of the report.
When you look at the average infection rate per thousand computers, you will notice that infection rates for more recently released operating systems are lower than for earlier ones.

Windows XP SP3 is showing an average infection rate of 15.9 computers per thousand. This figure drops to 7.5 on the most recent Vista version and 3.8 for Windows 7. The 64-bit editions of Vista and Windows 7 fare even better with 5.3 and 2.5 infections per thousand computers respectively.

operating system infection rates

32-bit Windows 7 computer systems are four times less likely to be infected with malicious software than Windows XP systems, and two times less likely than Windows Vista systems.

Comparison is even more favorable if you compare 64-bit editions. The 64-bit edition of Windows 7 is 6 times less likely to be infected than Windows XP.

Microsoft tries to explain the lower infection rate on 64-bit editions two-fold. One of the reasons may be that more tech savvy users pick the 64-bit edition of an operating system, the second that the Kernel Patch Protection feature of 64-bit Windows editions may contribute to that discrepancy as well.

infection rate trends

Infection trends confirm that 32-bit editions of Windows 7 have consistently had the lowest infection rates of all Windows 32-bit client operating systems.

Trojans, worms, adware, password stealers and other potentially unwanted software made up the bulk of infections world wide. Microsoft found significant location differences.

  • The United States and the United Kingdom, two predominantly English-speaking locations that also share a number of other cultural similarities, have similar threat mixes in most categories. Exceptions include Adware, which is more common in the UK, and Worms, which are more common in the US.
  • Brazil has an unusually high concentration of Password Stealers & Monitoring Tools, primarily because of the prevalence of Win32/Bancos, which targets customers of Brazilian banks.
  • China has a relatively high concentration of Miscellaneous Potentially Unwanted Software, Exploits, Backdoors, and spyware, and a relatively low concentration of Worms and Adware. China routinely exhibits a threat mix that is much different than those of other large countries and regions. Two of the most common threats in China, Win32/BaiduSobar and Win32/Sogou, are Chinese-language potentially unwanted software families that are uncommon elsewhere. The most common families in China also include a pair of exploits, JS/CVE-2010-0806 and
    JS/ShellCode, that were less prevalent elsewhere.
  • Adware dominates in France, led by Win32/ClickPotato.
  • Worms and Backdoors are unusually common in Spain. The top six families detected in Spain in 2010 were worm
  • The threat mix in Russia resembles that of the world as a whole, with the exception of an unusually low concentration of Adware, perhaps because of the highly language-dependent nature of online advertising.
  • In Germany, Trojan Downloaders & Droppers are nearly twice as common as in the rest of the world, led by Win32/Renos.
  • Korea has a large concentration of viruses, led by Win32/Parite, and worms. Viruses and worms have long been unusually common in Korea perhaps because of the popularity of public Internet gaming centers the where viruses are easily transmitted between computers and removable volumes.

Running a specific Windows operating system version does not necessarily mean that you will have a higher chance of infection, as that chance depends on the individual user. Experienced computer users can reduce the chance of infection significantly, both by expertise and experience, and security software that they have deployed on their system.

Still, if you are looking for an operating system for your parents, you may want to pick Windows 7 over a previous system.


Previous Post: «
Next Post: «


  1. Martin Turner said on May 18, 2011 at 4:52 am

    I use the free PC Security for Home Users from Secunia (PSI) designed to detect vulnerable and out-dated programs, really handy keeping your programs which are not auto up-dated, up to date and therefore not easy prey.

  2. said on May 15, 2011 at 6:52 pm

    “as that chance depends on the individual user” – so true!

    Imho security holes in other software are more often the cause of virus infection (not Windows itself) e.g. Flash, Reader, Java and IE (as updated versions are independent of Windows).

    We know most people don’t update these other programs so, the older the PC, the more out of date it becomes hence more virus infections.

    The big advantage of a W7 PC is not W7 per se but rather that the other software is more up to date than on most older XP/Vista PCs.

    We also find Microsoft’s statistics on virus infection rates to be laughably flawed, relying on the MS Removal Tool or MSE reporting is hardly likely to give a genuine picture of infection rates…

  3. David Macdonald Ajang said on May 15, 2011 at 3:43 am

    Using Windows 7 is no safer than using Windows XP if the user did not have an up-to-date antivirus installed. It’s probably because there are less loopholes in 7 compared to XP for malware could exploit to bypass antivirus protection & other security measures.

  4. Argoson said on May 14, 2011 at 11:42 pm

    OK, let me get the facts right: Microsoft says, that according to it’s own survey, and published by Microsoft… NOT third party, not another security firm… Microsoft… that Microsoft Windows 7 has less infections.

    Dos anybody else see the problem here ?

    Oh! And the words security and Intelligence in the same sentence, referring to Microsoft’s products…. Need i say more ?

Leave a Reply

Check the box to consent to your data being stored in line with the guidelines set out in our privacy policy

We love comments and welcome thoughtful and civilized discussion. Rudeness and personal attacks will not be tolerated. Please stay on-topic.
Please note that your comment may not appear immediately after you post it.