Oops: McAfee scan makes wrong diagnosis

McAfee enterprise and home users may have unnecessarily deleted or quarantined major files after a recent malware scan revealed a slew of false positives.

The company admitted on Friday that PCs employing a particular virus definition file – 4715 DAT – incorrectly identified many executables, including Microsoft Excel and Adobe Update Manager, as containing the W95/CTX virus.

"The 4715 DAT files contain an incorrect identification on W95/CTX," McAfee said Friday. "The (updated) 4716 DAT files have been posted to correct this issue. If you are seeing W95/CTX detection, ensure that you are running the 4716 DAT files or newer."

But McAfee's acknowledgement of the problem did not prevent a wave of criticism to be lobbed at the anti-virus giant.

"I need virus protection from my virus protection!" wrote one reader on technology source Slashdot.

The SANS Internet Storm Center recapped the woes of one system administrator who must deal with restoring 3,700 quarantined files.

"I started getting reports that looked like a virus outbreak, so I forced scans on all network machines," an administrator posting on the site said. "This turned out to make matters worse because of hundreds of files per machine were incorrectly identified as virus infected and quarantined. Many hours will be spent restoring these files from quarantine. Thankfully it was not set to delete the files."

Bloggers said false positives are not uncommon during virus scans, but a mistake to this degree should have been caught during the testing process.

A McAfee spokesperson did not return telephone calls seeking comment.

But the company offered a fix for affected parties.

"Users who have moved detected files to quarantine should restore them to their original location," McAfee said Friday. "Windows users who have had files deleted should restore files from backup or use system restore."

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