Feeds

Firefox leak could divulge sensitive info

How to remotely share your settings with people you've never met

Reducing security risks from open source software

A security researcher has discovered a vulnerability in Firefox that could allow criminals to remotely siphon private information stored in plugins and call sensitive functions.

According to an entry on the 0x000000 blog, Firefox generously enumerates all variables and registered objects that are present inside javascript files and on runtime and even allows the calling of certain functions.

This means ethically challenged hackers can remotely scan all variables set in Firefox plugins and use a simple AJAX script to log that information on a server.

While the ability to call functions stored in various plugins opens the possibility of denial-of-service attacks, the bigger risk from the vulnerability is that it will disclose information that could seriously compromise a user's privacy.

We're thinking of information stored in the Adblock plugin, for example. It includes a list of sites that have been whitelisted or blacklisted, giving snoops insights about a user's browsing habits. Even more problematic, would be details stored in extensions such as Gmail Checker or Boost for Facebook and dozens of other add-ons that personalize third-party websites.

"Depending on exactly what plugins you have installed it could be a problem," said Charlie Miller, principal security analyst for Independent Security Evaluators, who reviewed the 0x000000 blog post. "Using this particular vulnerability you could actually iterate and see what plugins are installed, which would be helpful if one of the plugins revealed information you wanted."

Miller was unable to access Adblock whitelist information using Proof-of-concept code 0x000000 made available, but he says that's likely a limitation of the code, not the vulnerability.

"I suspect its possible to get that information from the exploit," he told The Reg.

A Mozilla spokesman said the organization is investigating the report. As usual, the best workaround in the interim is NoScript, provided the site exploiting site has not been authorized to run javascript. ®

Mobile application security vulnerability report

More from The Register

next story
LibreSSL RNG bug fix: What's all the forking fuss about, ask devs
Blow to bit-spitter 'tis but a flesh wound, claim team
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
NUDE SNAPS AGENCY: NSA bods love 'showing off your saucy selfies'
Swapping other people's sexts is a fringe benefit, says Snowden
Own a Cisco modem or wireless gateway? It might be owned by someone else, too
Remote code exec in HTTP server hands kit to bad guys
British data cops: We need greater powers and more money
You want data butt kicking, we need bigger boots - ICO
Crooks fling banking Trojan at Japanese smut site fans
Wait - they're doing online banking with an unpatched Windows PC?
NIST told to grow a pair and kick NSA to the curb
Lrn2crypto, oversight panel tells US govt's algorithm bods
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Mobile application security vulnerability report
The alarming realities regarding the sheer number of applications vulnerable to attack, and the most common and easily addressable vulnerability errors.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.