Original URL: http://www.theregister.co.uk/2013/04/19/malwarebytes_false_positive/

Malwarebytes declares Windows 'malicious', nukes 1,000s of PCs

Biz boss apologies to the entire world

By John Leyden

Posted in Security, 19th April 2013 09:59 GMT

A dodgy software update for virus-killer Malwarebytes disabled thousands of PCs before a fix was issued this week.

Malwarebytes' database version v2013.04.15.12 erroneously flagged core Windows system files as malicious, resulting in unstable - and in some cases unbootable - machines. Windows system files were wrongly identified as Trojan-Downloader-ED.

The firm quickly pulled Monday's update and issued instructions on how to nurse crippled machines back to health. Despite its prompt response within minutes of the problem flaring up, thousands were still affected. Both consumer and enterprise users of Malwarebytes' technology were affected.

Marcin Kleczynski, Malwarebytes' chief exec, apologised for the botched update before later promising improvements in its update process.

From now on, anti-malware updates from Malwarebytes will be tested on a virtual server before they are pushed out into the world, we're told, a move that ought to identify at least more obvious problems.

Malwarebytes is best known for its freebie security scanner software but it branched out last September to target enterprises with a grown-up version of its tech.

False positives involving antivirus signature updates are a perennial problem that have affected nearly every vendors at one time or another. The consequent problems are most bothersome when they misidentify Windows operating system files as potentially malign and quarantine them, as in the latest case involving Malwarebytes. ®