Microsoft has made changes to its Security Essentials, Forefront and Defender software after it falsely identified Google's Chrome browser as a well-known online banking Trojan called Zeus and blocked it from users' computers. In an advisory bulletin released on Friday, Microsoft said the blocking of the browser was a mistake.
"On September 30th, 2011, an incorrect detection for PWS:Win32/Zbot was identified and as a result, Google Chrome was inadvertently blocked and in some cases removed," reads the advisory notice posted on their Malware Protection Center page. Microsoft said they had resolved the issue within a few hours and had released a manual update.
Initially Microsoft said it believed around 3,000 users were affected, but later said they expected to revise that figure. With just over 16 percent of the market share, it looks to increase drastically. That said, at the time of writing this, I have not had any issues with Google Chrome or MSE and both are functioning exactly as they should on my computer.
Users experiencing problems are advised to update the virus signature to the latest version, and then re-install Google Chrome. Google also updated its latest version of Chrome to 14.0.835.187 on saturday. In a blog post released by program manager Jason Kersey, the company noted that "these updates should help repair Chrome installs that were broken due to the issue with Microsoft Security Essentials."
On its official Google Chrome blog, the company has given detailed instructions on how to manually update the MSE signature files. A moderator on Chrome's help forum has also advised people to be cautious about allowing exceptions for Zeus in the antivirus software, as it is still active, and the Trojan presents a real risk in regards to stealing your data.