Microsoft Antivirus Flags Google Chrome as Malware
October 2, 2011

Microsoft Antivirus Flags Google Chrome as Malware

An estimated 3,000 PC owners who use Google Chrome to surf the Internet were unable to access (or in some cases, locate) the browser thanks to an error in Microsoft Security Essentials (MSE) antivirus software that flagged Chrome as malware.

On Friday afternoon, a post to the Microsoft Malware Protection Center Facebook page confirmed that "an incorrect detection for PWS:Win32/Zbot was identified and as a result, Google Chrome was inadvertently blocked and in some cases removed from customers PCs."

The post noted that the issue had already been fixed, and that "affected customers should manually update Microsoft Security Essentials (MSE) with the latest signatures. To do this, simply launch MSE, go to the update tab and click the Update button, and then reinstall Google Chrome."

According to Sara Yin of, the issue was initially discovered by Google Chrome's security team. The team reportedly began automatically began restoring the browser software for affected users, a process which was estimated to take a total of 24 hours.

"For those who don't want to wait, Google suggests removing the browser from your program list (browser history will not be deleted) and going to Chrome's homepage to re-download the software. Check its blog post for pictorial instructions," Yin added.

Slashgear's Rue Liu, Chrome had been "incorrectly identified as a member of the Zeus malware family." Zeus malware are typically Trojan horse style programs used by hackers to steal banking information by logging keystrokes, and are spread through unintentional downloads or phishing schemes.

Yin reports that Microsoft has been widely criticized for the error, "with some publications even saying the company was avenging a report suggesting Chrome could surpass Internet Explorer as the largest Web browser in the world."

Those reports suggest that Chrome will overtake Mozilla Firefox as the second most widely used browser before the end of the year, and could challenge Microsoft's Internet Explorer for the top spot, according to Gregg Keizer of Computerworld.

"Computerworld replicated Security Essentials' error by manually deleting chrome.exe, but had trouble reinstalling Chrome in Windows 7 using IE to download Google's browser," he wrote in a Sept. 30 article. "Only after uninstalling the remainder of Chrome, then using Firefox to download and save the Chrome setup file was Computerworld able to restore Google's browser."

"In that test, Chrome's bookmarks were reinstated," Keizer added. "Microsoft did not immediately reply to questions about whether the Security Essentials' snafu permanently eradicated Chrome bookmarks, as some users attested."


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