USB Autorun malware on the wane

Woman holding USB stickHere’s some good news in the ongoing fight against Windows-based malware – it appears that there has been a significant drop in the number of computers being infected by malware which exploits the Windows Autorun feature.

Autorun is the technology which makes a program start automatically when you insert a CD or USB stick into your Windows PC. You may have spotted the tell-tale Autorun.inf files in the root directory of your USB sticks and on CDs in the past.

Autorun may sound like it’s great for functionality, but a large amount of malware (the most notorious example would probably be the Conficker worm) has exploited the technology to infect computers via USB sticks in the past.

Earlier this year, Microsoft rolled out an update, effectively preventing Autorun malware from automatically infecting PCs without the user’s permission.

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And the good news is that it appears to have worked.

Microsoft chart of Autorun infections

According to research done by Microsoft, by May 2011 the number of infections found on scanned computers had reduced by 59% on XP and by 74% on Vista in comparison to the 2010.

Of course, disabling Autorun doesn’t mean the 100% eradication of all Autorun malware – as some examples use a variety of alternative techniques to spread beyond using the Autorun functionality.

Well done to Microsoft for removing most of the weeds from that particular corner of the malware garden.


Graham Cluley is an award-winning keynote speaker who has given presentations around the world about cybersecurity, hackers, and online privacy. A veteran of the computer security industry since the early 1990s, he wrote the first ever version of Dr Solomon's Anti-Virus Toolkit for Windows, makes regular media appearances, and is the co-host of the popular "Smashing Security" podcast. Follow him on Twitter, Mastodon, Threads, Bluesky, or drop him an email.

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