Microsoft's latest Security Essentials update inadvertently warned Internet Explorer (IE) users off Google.com.
Microsoft Security Essentials customers across the world began reporting on its user forum Wednesday that Google.com was being blocked within IE by a pop up message warning that it contained the Blackhole exploit kit, considered to be a serious malware threat.
What has turned out to be false security alerts -- labelled false-positives by antivirus companies -- began occurring shortly after Microsoft's latest security update, which fixed 21 vulnerabilities across its software.
While the warning could have meant Google.com was hosting a legitimate threat, the company has since clarified that on February 14 it introduced an incorrect detection for "Exploit:JS/Blacole.BW", referring to Blackhole.
Microsoft has recommended that Security Essentials customers download the latest definitions, noting that signature versions 1.119.1988.0 and higher include the update that corrects the problem.
The error on Redmond's part forced some customers to add Google.com and its related local domains such as Google.com.au to an exception list that bypassed its own definition.
Microsoft's false-positive error was first reported by security blogger, Brian Krebs.