Feeds

Firefox's Greasemonkey slippery on security

Full file exposure

  • alert
  • submit to reddit

Choosing a cloud hosting partner with confidence

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

Internet Security Threat Report 2014

More from The Register

next story
FYI: OS X Yosemite's Spotlight tells Apple EVERYTHING you're looking for
It's on by default – didn't you read the small print?
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Edward who? GCHQ boss dodges Snowden topic during last speech
UK spies would rather 'walk' than do 'mass surveillance'
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
'LulzSec leader Aush0k' found to be naughty boy not worthy of jail
15 months home detention leaves egg on feds' faces as they grab for more power
China is ALREADY spying on Apple iCloud users, claims watchdog
Attack harvests users' info at iPhone 6 launch
Carders punch holes through Staples
Investigation launched into East Coast stores
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.