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MOSFET
join:2002-09-29
Garfield, NJ

MOSFET

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Motorola Surfboard Hack Allows for Uncapping.

»www.theregister.co.uk/20 ··· conquer/

Old news but interesting to read.....

Cable modem hackers conquer the co-ax
By Kevin Poulsen, SecurityFocus
Published Thursday 5th February 2004 22:33 GMT

A small and diverse band of hobbyists steeped in the obscure languages of embedded systems has released its own custom firmware for a popular brand of cable modem, along with a technique for loading it -- a development that's already made life easier for uncappers and service squatters, and threatens to topple long-held assumptions about the privacy of cable modem communications.

The program, called Sigma, was released in its final version last month, and has reportedly been downloaded 350 to 400 times a day ever since. It's designed to be flashed into the non-volatile memory of certain models of Motorola's Surfboard line, where it runs in parallel with the device's normal functionality. It gives users almost complete control of their cable modem -- a privilege previously reserved for the service provider.
Click Here

The project is the work of a gang of coders called TCNiSO (»www.tcniso.net/). With about ten active members worldwide, the group is supported by contributions from the uncapping community -- speed-hungry Internet users who rely on TCNiSO's research and free hackware to surmount the bandwidth caps imposed by service providers, usually in violation of their service agreement, if not the law. To them, Sigma is a delight, because it makes it simple to change the modem's configuration file -- the key to uncapping, and, on some systems, to getting free anonymous service using "unregistered" modems. "I've known TCNiSO for two years now and I've done a lot of things with their techniques," wrote a Canadian uncapper in an e-mail interview. "Sigma is the greatest one I've seen."

To make Sigma work, uncappers (»www.securityfocus.com/news/394/) most commonly use a hardware hack developed by TCNiSO that tricks the Surfboard into accepting the custom code. Under an industry standard called DOCSIS (Data Over Cable Service Interface Specification), cable modems only permit changes to their internal programming that are sent down the pipe by the service provider -- users are prevented, Xbox-style, from running unapproved code, even on a modem they own.

But TCNiSO discovered that the Surfboard modem contains an undocumented vestigial console port, through which the boot process can be controlled. The group published a detailed tutorial for tapping into the serial port, which involves opening the modem and connecting two wires at particular points on the circuit board, then routing them through an inexpensive chip that converts the signal to RS-232 levels-- allowing the user to plug in a PC running a terminal program. Users less handy with a soldering iron can purchase a special conversion cable from TCNiSO's website to simplify the process.

From there, the user simply reboots the modem. A stream of text comes down the port describing the boot process, which the user can interrupt with a keystroke, then redirect by typing in a new boot string. The modem can be told to boot from any FTP server -- in this case, one running on the user's own PC, and serving up Sigma. Once the new firmware is loaded, it becomes part of the modem, and the process need not be repeated.

With Sigma installed, the cable modem lays exposed for what it really is: a versatile computer in its own right. Built on a powerful MIPS processor, the modem's native operating system is VxWorks (»www.windriver.com/produc ··· xworks5/), the same OS used by the Mars rovers. Sigma unlocks that hidden capability -- users can "rlogin" to the modem and interact with a VxWorks shell, or browse to a custom Web interface that sports easy-to-use and form fields for executing commands, or changing parameters normally controlled remotely by the service provider.

Eavesdropping Risks

While it's a boon to uncappers, the security implications of firmware hacking go beyond mere bandwidth-boosting and theft-of-service. The topography of cable modem networks typically puts between 500 and 1,000 homes in a neighborhood on the same circuit, their Internet traffic all mingled on the same co-ax cable. Subscribers are prevented from eavesdropping on their neighbors' traffic by their own modem, which is programmed to only pass packets destined for them. By building on TCNiSO's hacking technique, a malefactor could write custom code to forward all the raw network traffic to their PC.

Outside security experts have generally dismissed any eavesdropping threat on modern cable systems based on a belief that cable companies are encrypting customer traffic, a capability built into all DOCSIS-certified modems since 1999. But while encryption would indeed thwart any eavesdropping attempt, in the most commonly-deployed version of the DOCSIS standard, version 1.0, the encryption option is just that -- an option, and one that's turned off by default. "The security has to be there" in the modem, says Oscar Marcia, chief security architect at for CableLabs, the industry group responsible for DOCSIS. "But the [service provider] can decide when to turn it on."

And turning it on they are, Marcia says, but slowly, and in bits and pieces, even five years after the option became available. "It's kind of a gradual process... They want to make sure that they have all the kinks worked out of their system." He adds that he expects the process to accelerate as cable companies migrate to newer versions of the DOCSIS specifications, where encryption is "on" by default, instead of off.

SecurityFocus asked four U.S. cable modem service providers if they protected their customers with the encryption option. Comcast, Adelphia, and CableVision's Optimum Online declined comment; a spokesman for Time Warner's Road Runner service didn't return repeated phone calls on the question. Comcast's terms of service, however, acknowledges a risk of eavesdropping by "other subscribers," and Optimum Online's bluntly admits (»www.optimumonline.com/in ··· pe=terms) the company doesn't utilize encryption: "All Subscriber's ethernet traffic ... will be reflected by the cable Modem in an unencrypted form onto the cable network and be subject to eavesdropping."

The architecture of cable modem networks likely prevents eavesdropping of upstream traffic, liked typed passwords and credit card numbers, and websites using SSL would be immune from passive monitoring. "But downstream traffic is certainly visible to lots of people if crypto isn't used," said AT&T security researcher Steve Bellovin, in an e-mail interview.

The potential for spying and other mischief based on TCNiSO's research is not lost on "DerEngel" -- the 23-year-old unemployed programmer who heads the group. In an effort to be responsible, the group programmed Sigma to block execution of the VxWorks functions that change the modem's MAC address, a capability that could otherwise wreak havoc on a network in the wrong hands. And on the group's website, DerEngel offers to provide cable companies with a tool to detect Sigma in use. "If you're going to make the crack, might as well sell the glue," he says. So far, no one's taken him up on the offer.

International Team

DerEngel says he and a friend began hacking cable modems three years ago. Since then, the number of coders and researchers working on TCNiSO projects has grown to ten, each with specialized skill sets, hand-picked by DerEngel with the care of the roguish ringleader in a caper movie assembling a team for a big score. He has a C coder and a Windows programmer in Australia, a programmable memory expert in the U.K., testers in Europe and Canada, and an assembly language coder in Kentucky.

The latter is "Isabella," a 31-year-old programmer who coded Sigma from her home near Louisville. Isabella scratches out a living doing odd software and hardware jobs, like designing an electronic light toy, or writing the embedded code that operates the ghosts and goblins in a local haunted house attraction every Halloween. DerEngel approached her online last year, after hearing she was good with an assembler and might be interested in helping.

Underemployed and intrigued by the possibilities, Isabella wrote Sigma in three months of days-long spurts of creativity. She doesn't have cable modem service. "Everybody, it seems like, messes with PC-based stuff, but nobody that I know does the embedded thing," she says, explaining her interest in the project. "And Der is really nice. Some people think he's kind of crazy, but I figured out how to deal with it."

How crazy? When Isabella mentioned to DerEngel that she was looking for a better MIPS assembler for the job, she expected him to suggest one of the free programs already available. Instead, he wrote a new one from scratch, filling it with features particularly useful to firmware hacking. "He wrote a good assembler," she says. "Der was determined to do it."

Indeed, the accumulated talent of the group's members has begun to dwarf their raison d'être, and the coders seem to know it. DerEngel is barely interested in discussing uncapping, and speaks instead of the possibilities of writing plug-ins for Sigma -- extensible by design -- that would transform the capabilities of the Surfboard, turning it into a NAT box and a firewall. Isabella thinks they can program the modem to tune to the channels used by the cable companies' digital music feeds, which -- like TV programming -- share the co-ax with the cable modem service. The hack might let the modem send music to the user's PC, where it could be streamed in real time.

Ultimately, DerEngel and Isabella would even like to go legit, and turn the group into a research shop for cable system providers, or at least make a deal that allows TCNiSO to test their techniques in a sanctioned laboratory setting. But after three-years as the preeminent underground think tank for cable modem uncappers, DerEngel is realistic about the future. "In this industry you can't be the good guy and the bad guy," he says. "So I guess we have to hide for now, for that reason, because everyone will perceive us as the bad guys... I think they look at us as hacking something that we shouldn't, instead of just interested in electronics and trying to get better at what we do."

Of course, the cable industry has it's own impossible dreams, which include preventing smart coders with lots of time and restless passion from hacking the next generation of cable modems. "What you're talking about only affects the DOCSIS 1.0 modems," says CableLabs' Marcia of the Surfboard hack. The DOCSIS 1.1 and 2.0 specifications only accept firmware that's been digitally signed by the cable company. "Once you move to a DOCSIS 1.1, and we already have some cable operators deploying 1.1, this hack is not a viable hack any more.... One mistake, and it turns the modem into a brick."

But DerEngel doesn't believe any cable modem is going to be immune from customization, and he says his team is ready to prove it. "If you have to, you can just change the [programmable memory chip] -- desolder it, put it back on there," he says. "As long as the customer has the actual hardware in their hands, the customer will always be able to change what he has."

Copyright © 2004, 0 (»www.securityfocus.com/)
DerEngel
join:2006-01-02
San Diego, CA

DerEngel

Member

Yeah, almost two years old.

What the article failed to mention, was that there were already many hacks published before that did roughly the same thing (and many after). The key point being that this was only a single step in a long staircase.
Px
join:2005-04-30

Px

Member

And just to be the voice of reason here uncappingg can get you in big trouble and you can get charged with theft of service and sent to court by your ISP.

packetscan
Premium Member
join:2004-10-19
Bridgeport, CT

packetscan

Premium Member

which would be alot worse than just calling

captnhook
join:2001-02-20
NY

captnhook to MOSFET

Member

to MOSFET
Interesting reading MOSFET .. and welcome to BBR DerEngel
tired_runner
Premium Member
join:2000-08-25
CT
·Frontier FiberOp..

tired_runner to Px

Premium Member

to Px
said by Px:

And just to be the voice of reason here uncappingg can get you in big trouble and you can get charged with theft of service and sent to court by your ISP.
Not unless you can continue on unbrick and uncap a modem that's never been registered with CV, and was purchased on eBay from someone out in West Bubblefuck Arkansas or whatever.

JoshNJ
Premium Member
join:2001-12-25
Freehold, NJ

1 edit

JoshNJ

Premium Member

said by tired_runner:

Not unless you can continue on unbrick and uncap a modem that's never been registered with CV, and was purchased on eBay from someone out in West Bubblefuck Arkansas or whatever.
Which isn't possible, and even if it was they can track down where modems are connected from. Even unregistered ones.

Tzale
Proud Libertarian Conservative
Premium Member
join:2004-01-06
NYC Metro

Tzale

Premium Member

said by JoshNJ:

said by tired_runner:

Not unless you can continue on unbrick and uncap a modem that's never been registered with CV, and was purchased on eBay from someone out in West Bubblefuck Arkansas or whatever.
Which isn't possible, and even if it was they can track down where modems are connected from. Even unregistered ones.
It used to be, but now if it isn't registered it just forwards you to the registration page.
tired_runner
Premium Member
join:2000-08-25
CT
·Frontier FiberOp..

1 edit

tired_runner to JoshNJ

Premium Member

to JoshNJ
said by JoshNJ:

they can track down where modems are connected from. Even unregistered ones.
They can? Really?

Other than knowing which UBR is coming in from, how can they possibly trace it down?

JoshNJ
Premium Member
join:2001-12-25
Freehold, NJ

2 edits

JoshNJ

Premium Member

said by tired_runner:

how can they possibly trace it down?
They can hook their equipment up at each connection on their lines and follow where the signal is coming from. Same as if someone hooked up an rf modulator and starting sending out signals back out the cable lines. It is a lot of work, but they can do it.

(btw they don't have to start the the ubr, they would start from the node, which would limit their range they have to look at down to around 500 homes or less, and depending on the area, that could easily narrow it down between 2 or 3 apartment buildings.)
tired_runner
Premium Member
join:2000-08-25
CT
·Frontier FiberOp..

tired_runner

Premium Member

When you're talking The Bronx, this is not just two apartment buildings but more like five of them between a bunch of private houses.

Not to mention, a good portion of the Bronx comprises of utility poles running along the back of private houses, and to get there they'd need someone home to let them in.

My point being is not getting away with it, but rather them wanting to bother. In West Bubble Fuck Long Island it probably is cake. Here someone has to be home to let the tech in and take a look.

JoshNJ
Premium Member
join:2001-12-25
Freehold, NJ

4 edits

JoshNJ

Premium Member

said by tired_runner:

When you're talking The Bronx, this is not just two apartment buildings but more like five of them between a bunch of private houses.
I don't know what that is supposed to mean. A single node only passes so many homes/apartments. It is not like they have to check 20 blocks, with a 500 home max passed per node, especially where there apartments, that narrows it down very quickly. Not to mention the more likely candidates for doing such things would probably not be paying for any cable modem service, cross existing ool customers off the list and it gets to be a very small amount of connections they need to check.
said by tired_runner:

Not to mention, a good portion of the Bronx comprises of utility poles running along the back of private houses, and to get there they'd need someone home to let them in.
I didn't know we were talking about the bronx, but that doesn't make a difference. CV can get access to their equipment on poles anytime they wish. They do it all the time everywhere. Homeowners cannot deny them access to poles in their backyards.
said by tired_runner:

Here someone has to be home to let the tech in and take a look.
They would either come back or hop the fence from one of the neighbors, you think if the line broke and nobody was home in that one house they would just walk away and say nevermind. Of course not.
Shady Bimmer
Premium Member
join:2001-12-03

Shady Bimmer to tired_runner

Premium Member

to tired_runner
said by tired_runner:

When you're talking The Bronx, this is not just two apartment buildings but more like five of them between a bunch of private houses.
The location really makes no difference. The number of customer premises does (be it private homes or individual units in a multi-unit structure such as an apartment in a building).
Not to mention, a good portion of the Bronx comprises of utility poles running along the back of private houses, and to get there they'd need someone home to let them in.
The "utilities" with infrastructure on those poles has a legal right-of-way to enter private property to reach those poles. Nobody needs to be home to "let them in".

In fact, the poles themselves are most likely not on private property but rather on a right-of-way owned by the owner of the poles, even if it is only three feet wide.
My point being is not getting away with it, but rather them wanting to bother. In West Bubble Fuck Long Island it probably is cake. Here someone has to be home to let the tech in and take a look.
Theft-of-service is a major deal for MSOs (such as Cablevision). They don't take it likely and will go to extents to prevent theft, even if it is for a single individual. Unauthorized use of cable is a federal offense and the fines typically levied more than cover the MSO expenses in identifying the thieves.

MSOs could also block a "recurring" illegal modem at the node. Remember that the cable modem gets its "pool" (typically only one) of addresses for attached CPE devices (NICs) from the node. Similarly, the cable-modem itself has a unique MAC. Based on this there are multiple methods that may be used to prevent theft-of-service if it came down to it.
tired_runner
Premium Member
join:2000-08-25
CT
·Frontier FiberOp..

tired_runner

Premium Member

said by Shady Bimmer:

The "utilities" with infrastructure on those poles has a legal right-of-way to enter private property to reach those poles. Nobody needs to be home to "let them in".
I understand that. Like I said, the layout of houses around here makes it physically impossible for them to gain access. No such thing as gaps between houses or buildings. I don't know how the poles were erected in the first place unless they were in place before the real estate was built.

Someone needs to be home to get to the poles, either at the residence where they seek to investigate or a neighboring one.

This is why in places like Long Island this isn't an issue. The poles either run along the back or along the side. All they'd need to do is walk around someone else's backyard.

fcisler
Premium Member
join:2004-06-14
Riverhead, NY

fcisler to MOSFET

Premium Member

to MOSFET
If your modem's HFC MAC is NOT registered on their system, then you will be put in a "walled garden" until it is registered. This means like 64kb or 128kb cap, and i believe only access to CV's signup site. Unless you can provide your customer #, phone #, etc etc...you won't get out of this walled garden. ASSUMING you were able to get the QoS flows off of the local modem, i dont even think you'd be able to do anything but download REALLY quick from the signup page.