Re: Hacker pierces hardware firewalls with web page.

[david () lang hm]

I've seen several other posts where people make use of browser exploits to 
trick the browser into submitting a form to the router/firewall, and if 
the router has the default password, the attacker can then configure the 
firewall any way they want.

This sounds a little different. This sounds like it is exploiting standard 
protocols.

With FTP the client connect to the server, then at the start of a file 
transfer the client tells the server what port to connect to on the 
client. A 'helpful' firewall will watch for this message and reconfigure 
itself to allow traffic to that port. IIRC for FTP this data connection is 
one-way (with acks flowing the other way), but with SIP the port is used 
for data in both directions.

This sounds like the attacker is managing to use javascript to make a 
connection out that the firewall thinks is a protocol like this, and then 
by specifying the port they want to attack, tricking the firewall into 
opening that port up so that it can be attacked from the server the 
javascript connected to.

David Lang



On Fri, 8 Jan 2010, R. DuFresne wrote:

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> In reading this, I get the impression this is not a fault in the firewalls 
> themselves, but more an issue with the configuration of firewalls having been 
> 'tested' by this hacker.  Am I wrong in reading this news in that fashion?::
>
>
> January 6, The Register - (International) Hacker pierces hardware firewalls 
> with web page. On January 5, a hacker demonstrated a way to identify a 
> browser's geographical location by exploiting weaknesses in many WiFi
> routers. Now, the same hacker is 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 the hacker 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," the hacker told the 
> Register. "This defeats that security by visiting a simple web page. No 
> authentication, XSS, user input, etc. is required." The hacker's 
> proof-ofconcept 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 does not 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. Source:
> http://www.theregister.co.uk/2010/01/06/web_based_firewall_attack/
>
>
>
>
> Thanks,
>
>
> Ron DuFresne
> - -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        admin & senior security consultant:  sysinfo.com
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> These things happened. They were glorious and they changed the world...,
> and then we fucked up the endgame.    --Charlie Wilson
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