Home / Security / Mozilla Add-ons Serving Malware


Mozilla Add-ons InfectedThe most embarrassing thing about all this is that these infected experimental add-ons have been available for download for several months. How can Mozilla be unaware of this for that long?

According to Mozilla, version 4.0 of Sothink Web Video Downloader is infected with password sniffer Win32.LdPinch.gen and Master Filer is infected with the backdoor Trojan Win32.Bifrose. This Malware has infected Windows systems following installation of the infected browser add-on.

Uninstalling the add-on will not remove the infection from your computer. Mozilla lists several anti-virus programs in its advisory that are able to recognize the Malware and remove it from the infected computer.

Both infected add-ons have been downloaded a total of 4,600 times from the Mozilla official download site. The infected add-ons were only discovered and removed, on January 25 and February 2, following use of additional anti-virus scanning software by Mozilla.

Users shouldn’t panic as only a small amount of computers were infected. It’s more than likely that your antivirus software will recognize and remove the infection.


About the author: Frank Jovine


The idea for Tech Jaws and most of the look of the site came from Frank’s mind – a place you wouldn’t want to vacation. Frank takes his run of the waters up North, and has been building successful web sites for years. He’s a regular within social communities like Facebook, Twitter, StumbleUpon, Reddit and Digg. His favorite appetite for tech savvy web sites include, TechCrunch, ZDNet, and helping members in Yahoo Answers in the Computer category.


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  1. I’ve been downloading a lot of add-ons recently since the release of Firefox 3.6. I’m glad I didn’t get either of those.

  2. The only thing I do with my Mozilla firefox browser is to upgrade it. Lucky thing, I’m not really into add-ons. Good thing that only a few computers were infected but even if this is the case, mozilla should be more aware of the situation of their product if they don’t want to lose users and followers.

  3. Hm, well maybe there are more infected add-ons out there or some viruses targeting them, because recently I had problems with Trojans on my computer which were changing settings on some of my add-ons. After removing suspicious add-ons they disappeared or at least I hope they did.

  4. I heard that Mozilla has a strong malware checking strategy, but why this happened?

    I think now we have to think twice before installing any new add-on from Mozilla.

    • JK,

      I wonder how many other add-ons are infected. I use the same 5 add-ons and I trust what I am using only because I test everything before I install it on a test PC.

  5. thx Frank for the heads up.

  6. I can’t believe Mozilla allowed this to happen. Luckily, I do not think that I downloaded either of those two add-ons. Come on Mozilla, you’re better than that.

  7. Exactly one of the main reasons I love Mac’s. No need to say anymore.

  8. waaaa, Thank you for sharing it.. I’d better shift to mac right now..

  9. I use about 7 add-ons and I am glad I didn’t get infected as well and i like to recommend Mozilla.

  10. I had installed mozilla firefox for 2 years and during this period of time I had installed about 40 add-ons of Mozilla but like the one of comments i’m glad that I didn’t get any infections this I say because Imy antivirus doesn’t detect any malware infections.

  11. I had more than 20 add-ons but I didn’t get infected as well

  12. merciiiiiiiiiiiiiiiii

  13. Merchant Capital Cash

    Thanks for sharing this, never think that the addon on the official site of mozilla can be afftected by the malware…

  14. applied cognitive psychology

    Really the most embarrassing thing about all this is that these infected experimental add-ons have been available for download…….

    Mozilla very best browser then all browser.

    Thank you