Developers of the popular LastPass password manager rushed to push out a fix to solve a serious vulnerability that could have allowed attackers to steal users' passwords or execute malicious code on their computers.
The vulnerability was discovered by Google security researcher Tavis Ormandy and was reported to LastPass on Monday. It affected the browser extensions installed by the service's users for Google Chrome, Mozilla Firefox and Microsoft Edge.
According to a description in the Google Project Zero bug tracker, the vulnerability could have given attackers access to internal commands inside the LastPass extension. Those are the commands used by the extension to copy passwords or fill in web forms using information stored in the user's secure vault.
If the extension's binary component is installed, the "openattach" command can be used to run arbitrary code on the computer, Ormandy said on the bug tracker.
The LastPass developers deployed a workaround on their server to prevent exploitation and plan to include a full fix in new versions.
On Tuesday Ormandy reported another vulnerability in the Firefox extension that, according to the LastPass developers, was related to the first one. That vulnerability was fixed in a new version of the Firefox extension, 4.1.36a, that was released Wednesday.
"We have no indication that any of the reported vulnerabilities were exploited in the wild, but we’re doing a thorough review at this time to confirm," the LastPass developers said in a blog post. "No password changes are required of users at this time."