Pair of flaws pop up in Firefox

A security company has reported two new flaws in the Mozilla Firefox browser that may leave locally saved files vulnerable to outside attacks.

Both flaws were announced by SecuriTeam, a division of Beyond Security, this week. The first flaw lies in Firefox's pop-up blocker feature, according to a SecuriTeam statement. The browser typically does not allow websites to access files that are stored locally, according to the official report, but this URL permission check is superseded when a Firefox user has turned off pop-up windows manually. As a result, an attacker could use this flaw to steal locally stored files and personal information that might be stored in them.

A possible scenario for such an attack would involve the user clicking on a malicious link that would furtively plant a target file equipped with an exploit code on the computer's hard drive. Then it would display a prompt asking the user to allow a pop-up to appear in order to play a video file or download. The attacker-supplied file would then be loaded thanks to the browser flaw, which could give the attacker local file read privileges.

It appears this flaw may only apply to older versions of Firefox, prior to the current 2.0 release but Beyond Security was unavailable for comment on the matter.

The second flaw, announced by SecuriTeam yesterday, concerns Firefox's phishing protection feature. With this vulnerability, an adept phisher could fool the browser into believing a fraudulent site is actually secure by adding particular characters into the URL of its website.

The phishing flaw does appear to apply to the current 2.0.0.1 version of Firefox.

Mozilla was unavailable for comment at the time of writing.

Caroline McCarthy writes for CNET News.com