Faulty signature updates on Wednesday resulted in Symantec's anti-virus packages falsely identifying that Yahoo! mail was contaminated by malware.

The webmail service, currently in beta, was wrongly labelled as being contaminated by the Feebs worm (http://www.symantec.com/security_response/writeup.jsp?docid=2006-013122-5631-99) as a result of the snafu (http://isc.sans.org/diary.html?storyid=2319).

Symantec published a signature update later on Wednesday that resolved the problem.

Updates to security software signatures can occasionally result in false alarms against legitimate applications, a problem far from confined to Symantec. For example, in November Microsoft's Windows Live OneCare warned that Gmail was infected by malware.

And in February 2006, an update to Microsoft anti-spyware incorrectly labelled two versions of Symantec's anti-virus software as Trojan horse malware. ®

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