Mozilla Distributes Virus-Infected Language Pack
Anyone who downloaded the Vietnamese language pack for Firefox 2 needs to run an anti-spyware and anti-virus scan, then disable the pack for now. Mozilla warned yesterday that all versions of that language pack downloaded from its servers since Feb. 18, 2008, were infected with pop-up ad serving software.
Window Snyder, Mozilla’s chief security officer, said the Vietnamese language pack was contaminated as the result of a virus infection. “This usually results in the user seeing unwanted ads, but may be used for more malicious actions.”
Snyder said Mozilla doesn’t know how many people downloaded the compromised language pack, but said there have been 16,667 downloads of the pack since November 2007.
Mozilla is working on getting a replacement language pack up on the site soon. Snyder said that while Mozilla does virus scans when add-ons are uploaded to its servers, the scanner for whatever reason didn’t catch this nasty until several months after the upload. Mozilla is now adding post-upload scans to everything on its download servers, she said.
Language packs are add-ons in Firefox. Add-ons can be removed by clicking “Tools” and then “Add-ons.” According to the discussion on this in the Bugzilla database, the culprit here is something called “Trojan.Win32.Xorer,” which disables security software on the infected PC and spreads by infecting files, programs and removable drives.
The Vietnamese language pack for Firefox 2 contains inserted code to load remote content. This code is the result of a virus infection, but does not contain the virus itself. This usually results in the user seeing unwanted ads, but may be used for more malicious actions.
Everyone who downloaded the most recent Vietnamese language pack since February 18, 2008 got an infected copy. While we cannot determine the exact number of compromised downloads, there have been 16,667 total downloads of the Vietnamese language pack since November 2007, so we anticipate the impact on users to be limited.
Mozilla does virus scans at upload time but the virus scanner did not catch this issue until several months after the upload. We are also adding after-the-fact scans of everything to address this sort of case in the future.
A new language pack will be available shortly. Until then, Vietnamese language pack users should disable this package using the add-ons dialog on the Tools menu.
https://bugzilla.mozilla.org/show_bug.cgi?id=432406
source:blog.washingtonpost.com/securityfix/2008/05/mozilla_distributes_virusinfec_1.html
