False positive problem hits avast! users

Posted by   Virus Bulletin on   Dec 9, 2009

Human failure blamed for faulty update.

A relatively small subsection of the massive user base for Alwil's ever-popular avast! products were hit by a string of false positives last week, which in some cases saw vital Windows components quarantined or deleted.

An update released in the very early hours of Thursday morning (00:15 GMT) apparently caused avast! to detect 'hundreds of innocent files', misidentifying them as Delf or Zbot worms. Affected software included items from respected publishers such as Adobe and Realtek, as well as driver files. The issue was spotted and a fix issued within six hours, so the vast majority of users, whose systems were not active during this time, missed out on the update and thus the problems it brought. Nevertheless, with around 100 million avast! users worldwide, a significant number of people will have been affected.

According to unusually detailed information made available by the firm on blogs and forum postings, the problem was caused by a non-standard update released to fix a minor issue observed by some users of the forthcoming avast! 5 beta. The update was apparently issued by non-specialist personnel and bypassed the usual quality assurance process, which would have quickly flagged the blatant false alarming issue and stopped the release.

Alwil has been quick to offer assistance to anyone affected by the issue, and has provided full technical details in a support article here. Explanations of the causes of the problem, and efforts being made to ensure it is not repeated, are in a forum thread here and a blog entry from Alwil CEO Vincent Steckler here.

Posted on 09 December 2009 by Virus Bulletin

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