Mozilla on Friday said that it had removed two Firefox add-ons from its Web site because they installed malware. "Two add-ons in the experimental section of addons.mozilla.org were found to be containing malware," Mozilla said on its security blog. "These were not originally detected with the anti-malware scanning tools that we have been using. We have since increased the number of scanning tools, and will be taking additional steps to minimize the risk of further incidents."
AMO, Mozilla's add-on management group, posted a notice about the malicious add-ons on Thursday.

The malicious add-ons have been identified as version 4.0 of Sothink Web Video Downloader and all versions of Master Filer. According to AMO's blog post, Sothink Web Video Downloader 4.0 included malware known as Win32.LdPinch.gen, while Master Filer included malware known as Win32.Bifrose.32.Bifrose Trojan.

Launching Firefox with either of these add-ons installed on a Windows computer is likely to lead to an infection. Removing the add-on does not remove the trojan software, however. Antivirus software that recognizes the malware is necessary for removal. According to Mozilla, the following antivirus apps will work: Antiy-AVL, Avast, AVG, GData, Ikarus, K7AntiVirus, McAfee, Norman, and VBA32.

Last May, security researcher Duarte Silva created a proof-of-concept malicious add-on, or "maladon," to highlight problems in Firefox's add-on security model.

The link for this article located at Information Week is no longer available.