A new virus definitions update for Microsoft’s Security Essentials (MSE) has inadvertently misidentified Google’s Chrome browser app as containing a trojan and being a “severe” threat. MSE has been caught removing Chrome from users’ computers. Microsoft has acknowledged the mis-categorization and issued a patch, but not before hundreds of users were forced to reinstall the browser on their computers.
MSE accidentally reported the malware Win32/Zbot was hidden in the Chrome app. Win32/Zbot is a password-stealing trojan that looks for visits to certain Web sites. It can then allow limited backdoor access and control and may terminate certain security protection, making a user’s computer vulnerable to attack.
The protective actions by MSE apparently did not affect all computers running the MSE definitions. It’s likely that the problem could have been caused by an interaction with a third app present on some users’ computers.