Feeds

Hacker pierces hardware firewalls with web page

No interaction required

The essential guide to IT transformation

On Tuesday, hacker Samy Kamkar demonstrated a way to identify a browser's geographical location by exploiting weaknesses in many WiFi routers. Now, he's back with a simple method to penetrate hardware firewalls using little more than some javascript embedded in a webpage.

By luring victims to a malicious link, the attacker can access virtually any service on their machine, even when it's behind certain routers that automatically block it to the outside world. The method has been tested on a Belkin N1 Vision Wireless router, and Kamkar says he suspects other devices are also vulnerable.

"What this means is I can penetrate their firewall/router and connect to the port that I specified, even though the firewall should never forward that port," Kamkar told El Reg. "This defeats that security by visiting a simple web page. No authentication, XSS, user input, etc. is required."

Kamkar's proof-of-concept page forces the visitor to submit a hidden form on port 6667, the standard port for internet relay chat. Using a hidden value, the form surreptitiously coerces the victim to establish a DCC, or direct client-to-client, connection. Vulnerable routers will then automatically forward DCC traffic to the victim's internal system, and using what's known as NAT traversal an attacker can access any port that's open on the local system.

For the hack to work, the visitor must have an application such as file transfer protocol or session initiation protocol running on his machine. The hack doesn't guarantee an attacker will be able to compromise that service, but it does give the attacker the ability to probe it in the hope of finding a weak password or a vulnerability that will expose data or system resources.

"Most people have this false sense of security that 'well, I'm behind my router, nobody can connect to my ports,'" said Kamkar, the hacker behind the notorious Samy Worm that in 2005 took MySpace out of commission by adding more than 1 million friends to the author's account. "If you're going to keep a service open to the world, you'll probably have more upkeep" to make sure it's secure.

The problem is a hard one to solve, since NAT, short for network address translation, is included in many routers to give users a seamless experience when accessing a host of internet-based services and applications. The use of a software-based firewall on the client will help, but Kamkar warned that even then some ports may be accessible.

While Kamkar's proof-of-concept requires users to press a submit button, he said it's trivial to use javascript so no interaction is required after the page is visited.

Kamkar said he based his attack on IRC because many versions of Linux used to run routers support the protocol by default. He's based similar attacks on file transfer protocol and had success with both the Belkin and Airport Extreme routers and believes other services such SIP may work on those routers as well as other devices.

Your reporter was unable to get the IRC attack to work on a Netopia 3347-02, so mileage obviously varies. We're interested in hearing from Reg readers about what other routers are vulnerable. To test whether the attack can pierce your firewall, visit this page and specify the port of a service that's already running on your system. ®

Next gen security for virtualised datacentres

More from The Register

next story
Ice cream headache as black hat hacks sack Dairy Queen
I scream, you scream, we all scream 'DATA BREACH'!
Goog says patch⁵⁰ your Chrome
64-bit browser loads cat vids FIFTEEN PERCENT faster!
KER-CHING! CryptoWall ransomware scam rakes in $1 MEEELLION
Anatomy of the net's most destructive ransomware threat
NIST to sysadmins: clean up your SSH mess
Too many keys, too badly managed
Scratched PC-dispatch patch patched, hatched in batch rematch
Windows security update fixed after triggering blue screens (and screams) of death
Researchers camouflage haxxor traps with fake application traffic
Honeypots sweetened to resemble actual workloads, complete with 'secure' logins
Attack flogged through shiny-clicky social media buttons
66,000 users popped by malicious Flash fudging add-on
New Snowden leak: How NSA shared 850-billion-plus metadata records
'Federated search' spaffed info all over Five Eyes chums
Three quarters of South Korea popped in online gaming raids
Records used to plunder game items, sold off to low lifes
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?