Original URL: http://www.theregister.co.uk/2008/11/11/avg_false_positive/

AVG slaps Trojan label on core Windows file

Second false alarm creates consternation

By John Leyden

Posted in Security, 11th November 2008 12:36 GMT

Some users of AVG were left with unusable Windows systems after the popular AVG security scanner software slapped a Trojan warning on a core Windows component.

AVG tagged user32.dll as a banking Trojan following a signature update issued on Sunday, advising users to delete the "harmful file". Users following this advice would be left with systems that either failed to boot or went into a continuous reboot cycle, according to dispatches from those hit by the glitch.

Users of both AVG 7.5 and 8 (free and full fat editions) were hit by the snafu. AVG has admitted the problem and responded by posting advice on how to recover affected systems (via its support forum item 1574 - here). The company has also updated its virus definition files to purge the false alarm detection from its virus signature database.

False alarms by anti-virus scanners have affected just about every security vendor at one time or another. The issue causes more inconvenience when Windows files are flagged as potentially malicious, as in this case with AVG, so its no surprise to find that AVG's support forums are filling up with complaints.

This is not the first such false positive AVG has had to fix. Its software wrongly identified CheckPoint’s Zone Alarm as a Trojan less than a month ago, raising questions about the quality control regime for virus definition updates released by the Czech-based firm, best known for the popularity of the cut-down version it offers to consumers at no cost. ®