Firefox's Greasemonkey slippery on security
Full file exposure
Posted in Security, 20th July 2005 16:43 GMT
Watch Now : Virtual Machine Movement with Hyper-V
A severe security hole in Firefox's Greasemonkey extension has been uncovered that exposes any file on a user's local hard drive to a hacker.
The vulnerability affects PCs and Macs and means a hacker does not need to know an exact file name before diving into a system. According to one online posting, typing something such as "file:///c:/" will return a parseable directory listing. Macs can be hacked in a similar way.
Mark Pilgrim, a coder and author writing about Greasemoney, told a Greasemonkey mailing list: "This particular exploit is much, much worse than I thought. GM_xmlhttpRequest can successfully "GET" any world readable file on your local computer.
"And because GM_xmlhttpRequest can use POST as well as GET, an attacker can quietly send this information anywhere in the world," Pilgrim warned.
Greasemonkey enables developers to add DHTML to a web page, in order to change that page's behavior.
Users have been advised to either completely un-install the Greasemonkey extension or downgrade to Greasemonkey to 0.3.5 - a "neutered" version that lacks the APIs making Greasemonkey scripts more powerful than regular HTML.
A fix is in development and expected to take a few days, according to Greaseblog - the Greasemonkey blog®
Related stories
Hackers attack Mozilla site to spread spam
Firefox update completes busy patching day
Firefox spoof bug returns from the dead

Data control in the cloud
The new Office Garage series:
IT infrastructure monitoring strategies