New Firefox Malware


Apparently BitDefender stumbled upon a Firefox-only banking malware. It installs itself as a Firefox plugin (= it installs a native binary) and as a javascript file in the Chrome folder (= it modifies the source code of Firefox):

  • %ProgramFiles%\Mozilla Firefox\plugins\npbasic.dll
  • %ProgramFiles%\Mozilla Firefox\chrome\chrome\content\browser.js

If anyone has a sample, I’d like to have a look at it. It’s not technically a Firefox extension, but its payload could also be delivered as an extension (with no native code at all). If anybody wonders why there is not more Firefox crapware, there are two reasons for it:

  • the browser market is still dominated by IE
  • malware authors have not realised how easy it was to write malware for Firefox



Malicious Firefox Extensions – continued

I worked with Phil on malicious firefox extensions – very briefly at SSTIC, in details on the lab’s blog, and in an unpublished short paper.

As some people asked, yes the issues have been reported to the Mozilla security team (thanks to JP Gaulier and Tristan Nitot). And the result is a bug report marked as invalid (which is normal, since what we wanted to communicate was not a bug report but rather design issues).

So basically the situation is: ActiveX is bad because there is absolutely no security policy. There is absolutely no security policy for Firefox extensions but it’s cool.

I’m out, I really need a double shot of espresso now.