Microsoft says RIP Windows XP AutoRun for USB

The feature that became an attack vector.

Microsoft has finally decided to push out a Windows update that should stop attempts to exploit AutoRun with a USB stick.

AutoRun is a feature of the Windows operating system that fires up any program once a USB or CD/DVD is inserted into a computer.

In recent years hackers have increasingly turned to AutoRun, which permits programmers to deliver instructions via Autorun.inf files to run programs without first gaining user permission.

The problem for Microsoft was that while the obvious solution was to disable AutoRun, it was considered a legitimate feature, which happened to be exploited by the Conficker worm, Rimecud and Taterf.

"AutoRun isn't an accident -- it's by design, and as I mentioned we care about the very real positive uses of the feature. In other words, in a very real sense, it's not a bug, it's a feature," said Adam Shostack, a Microsoft security program manager.

So Microsoft wasn't calling its Windows Update a "security update" but rather an "Important, non-security update" which effectively disabled AutoRun.

The feature remained in Windows 7 but Microsoft claimed to have largely addressed AutoRun abuse. One of its reasons for issuing the "non-security update" was that it found that Windows XP users were 10 times more likely to get infected when faced with such an attack.

First introduced in Windows 95, the feature has caused security professionals frustration. In 2008, infected digital picture frames exploited the feature and while it was possible to disable AutoRun, doing so was not an easy task.

At last year's AusCERT security conference IBM accidentally issued delegates a thumb drive which exploited AutoRun.