Same sh*t, different zero-day

An unpatched memory corruption flaw in the latest version of Firefox creates a means for hackers to drop malware onto vulnerable systems.

Security notification firm Secunia reports that the security bug (which it describes as extremely critical) stems from errors in handling JavaScript code. The flaw has been confirmed in the latest 3.5 version of Firefox, released in late June.

Older versions of the popular alternative browser might also be affected, Secunia warns.

Exploit code has been uploaded onto recently revived security exploit website milw0rm, a factor that could hasten the development of more attack code.

Secunia advises Firefox users to avoid browsing untrusted websites or following untrusted links pending the availability of a fix from Mozilla (there's nothing in the pipeline just yet: http://www.mozilla.org/security/announce ).

The appearance of an unpatched vulnerability in Firefox could hardly have come at a worse time because it coincides with confirmation from Microsoft on Monday of a second unpatched ActiveX flaw affecting users of its Internet Explorer software.

Only one of these two security bugs is likely to be fixed later on Tuesday, when Microsoft publishes its monthly Patch Tuesday update. That prompted some security researchers, including those at the SANS Institute's Internet Storm Centre, to consider the use of an alternative browser on the grounds of security.

Selecting Firefox over IE when both have unresolved security problems fails to make much sense, leaving Windows users looking for more secure surfing software alternatives with a choice limited to Opera, Safari and Google Chrome.

(Register)