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ATPM 13.06
June 2007




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Book Review

by Eric Blair,

Hacking the Cable Modem


Author: DerEngel

Publisher: No Starch Press

Price: $30

Trial: Chapter 17

Alright, let’s get this out of the way right now—Hacking the Cable Modem is not a Hacks book. If you pick this book up thinking you want to squeeze a little extra out of the cable modem the Comcast guy just installed, put the book down and walk away. Hacking the Cable Modem is aimed at people who are willing to get into the guts of their cable modem and override the restrictions put in place by the cable companies. The sample chapter should give you a decent idea of the book’s target audience; it’s entitled “Building a Console Cable.”


If you’re still here after my clarification and still interested in taking a whack at your cable modem, then you’re in the right place. Before going too deep into what the book offers, though, I want to mention two caveats. First, I did not attempt any of these hacks. I didn’t expect the book to be as in-depth as it turned out to be, and I wasn’t comfortable with the concept of modifying my leased cable modem. Second, most of the techniques discussed in the book are examined from a Windows-centric viewpoint. With some research, you could probably replicate some of the techniques on OS X, but others might require temporarily switching over to Windows.

The book’s 23 chapters basically fit into three different sections: background, basics of hacking, and hacking specific modems. The background section covers the evolution of the cable modem. This starts with the earliest days of cable Internet access, when pretty much every type of cable modem used a different technique for connecting the user to the Internet. As a result, users pretty much needed to use an ISP-provided cable to ensure a reliable connection to the Internet. The history continues through the development and evolution of the DOCSIS standard, which established the protocols for ISP and cable modem producers and opened up a variety of modem options for end-users.

The background section also covers the history of cable modem hacking. This includes the birth of these practices and the author’s extensive experience with hacking cable modems. Personally, I found most of this material a bit dry, though I can understand why some people would want to have this information, particularly those people interested in modifying the guts of their cable modems.

Jumping ahead, the book ends with four chapters on hacking specific cable modems. Consider this the “cheat-sheet” section of the book. If you desired, you could use the book as a buying guide for your next cable modem purchase. You probably don’t want to perform these hacks on a leased cable modem, so you may as well buy a modem for which you’ve got instructions.

One of the dangers of referencing particular products is that the material can rapidly become dated as companies update their product lines. Hacking the Cable Modem’s middle section, related to the basics of hacking, helps to alleviate this concern. Over the course of 13 chapters, DerEngel delves into information and techniques necessary to understand cable modem hacking. Most of the information is presented within the context of hacking a Motorola SURFboard, but DerEngel provides enough information that a motivated hacker can adapt the information to another cable modem. The only concern I have about obsolescence is whether changes to the DOCSIS standards may invalidate some of the information in the book.

Although Hacking the Cable Modem was not the book I hoped, I still found it to be an interesting reference. If you own a cable modem and are interested in breaking out the soldering iron, I definitely recommend checking out the book. It’s a little dense at times and you definitely need to understand what you are doing, but the book definitely feels like a comprehensive reference on getting the most out of your cable modem.

Reader Comments (21)

Anwar Shiekh · June 3, 2007 - 11:37 EST #1
Thought I should add this from the site

Real title should be "How to become a thief"!, February 9, 2007
By Stratman56 "Rob" (Orlando, FL USA)

I find it really disgusting that books like this are out there under the guise of "free speech". This is a how-to book whose sole purpose is to teach you how to commit a crime! That's right - hacking your cable modem is a crime! In most states, a felony. It's called Theft of Services, and carries some rather stiff penalties. I used to work for a cable Internet provider in their security department, and I can tell you that I have personally watched people hauled away in handcuffs for following the directions given to them by this author on his website (did he mention that hacked modems are NOT undetectable?).

Bottom line - regardless of the respective legalities, it's stealing. It costs the cable companies money to provide bandwidth. The more bandwidth they need to provide, the more the cost to them, so they have to charge for more bandwidth. Cable is also a shared bandwidth technology. If you are stealing bandwidth, this is bandwidth the company is not allotting for - who do you think loses then? Your neighbors. All of a sudden, the broadband connection they ARE paying for slows to a crawl.

This book is another example of a really sad state of affairs today - the fact that more people every day join the morally bankrupt who believe that right and wrong do not matter. All that matters is whether or not something benefits them.
zack · July 9, 2007 - 20:32 EST #2
Actually most cable companies control bandwidth from the server side so it doesn't matter, besides that you aren't stealing someone elses bandwidth, you are just taking advantage of the extra bandwidth that no one is using.
BlackCow · September 5, 2007 - 14:43 EST #3
@Anwar Shiekh

Although I agree with you that it is illegal (we should be pushing to improve the network in the US for everyone, not stealing for yourself) I find it really disgusting that you think a book with knowledge about how cable modems work should not be free speech. Knowledge is not a crime.

Also it should be noted that a lot of people turn to this because they are sick of their ISP throttling their bandwidth and want to get what their ISP advertised.
Anwar Shiekh · September 5, 2007 - 17:27 EST #4
What of ownership?

Can not a company own an idea it has invested in?
Same goes for software development.

To take that knowledge without due payment might well be 'inappropriate'
BlackCow · September 6, 2007 - 01:12 EST #5
Aren't cable modems standard, whats so wrong about understanding how things work. Its not what you know its what you do with what you know.
Brian P · October 17, 2007 - 15:04 EST #6
Hey first off, I have been ousted for this very tactic. I did not do any hardware altering to my modem however I did do software hacking, which made a difference when optimum online first came out. They were still perfecting their system.

After sapping up bandwidth from neighbors and neighboring companies they complained about slow speeds. They cable company figured out it was my line using all the bandwidth and issued me a summons. They said I was stealing speed from them and other users. They threeatened to terminate my service indeffinetly. Since then I have not tried to "get one over" on my ISP. It is however good knowledge to know how these devices work and if your ISP blows you off because you are not getting the service you are supposed to you can get them back.
Dave · July 4, 2008 - 14:09 EST #7
I own a small Cable Company and we provide High Speed Internet.

We have about 315 subscribers (which for our small company is over 50% versus video subs.

Anyway, Stealing bandwidth is a crime! You are not changing a demarc point. You are stealling bandwidth that the cable company has to pay for.

A full t-1 which is only 1.5 meg sym. alone runs over $1,000 per month. To give a customer this "upto Speed" at an affordable residential price.. we have a formula that tells us on average how many users set to what speeds will keep the bandwitdth for all of them flowing as close to the upto speed as possible.

We keep track of how many users we are billing at what speed packages. This is a service to our subscribers as they can reach very close and a lot of times the complete upto speed while not paying an arm and a leg. For instance we run a 10meg connection for as low as $42.33 in our bundle pack. It would cost the customer around $4,000 a month plus buildout cost/ installation to get somthing like this.

When you take bandwidth that you arent paying for, the cable company is still paying for it. Thiefs like that - slow down the network. And hey... It is VERY EASY for us to see your Modem/ its upto speed it's mack address - model/brand as well as the computer/brand and mac. And it is VERY easy to trace down the house the modem is in. If you are caught - you will go to jail! I have had warrants swore out on several people for "Thieft of Services".

If you hack a cable modem - your are a thief! Dont kid yourself and rationalize what you are doing. You are stealing bandwidth that someone is having to pay for. It is not free to the cable company. And it isnt the EVIL Cable Co who just loves to throttle your speed. It cost money. The more subs we have the faster speeds we can afford to run.

Knowledge is not a crime. Read all you want. But the second you hack that modem into a cable network.. you have become a thief.
Dave K · November 7, 2008 - 03:35 EST #8
I do agree that stealing of resources that you are not paying for is both wrong and illegal, however knowledge is power, for instance I know how to pick locks very well but that does not mean I go out and rob houses, and this knowledge has come in very handy many times in my own life for very legit reasons (ie, locked out of my house or car, helping a friend in the same situation, and even increasing my own security methods to prevent theft).

Now my experience so far after being a computer store owner for a few years. Most ISPs these days screw the customer over hard core. They will tell a customer that they should be getting up to 3meg for instance and then after having the service for a few months they start throttling the speed way down, this is especially true for people who use P2P networks such as Skype, and Bit torrent even if they are using it for legal file sharing, such as game updates, internet calling, open source software, ect. So instead of that customer getting there quoted speed they will get sometimes 1/4 of the quoted speed which is complete bullsh*t when they are paying $60 or more for that connection. I understand that a corporate class connection costs money but its not as high as mentioned in other posts. For instance at the computer store we are paying for a FULL T3 between our store and the store next door to us and we split it 50/50 so we each get about 21.5Mbit/s which means we can download or upload a single file at about 8 Megabytes/second and all total the connection is costing about $3000/month for each business through AT&T, We used to have 4 FULL T1 lines that were costing us about $1,100/month so the price of each was about $275. The thing to remember is that the price of the connections can be lower or higher depending on you proximity to the provider when you start dealing with these types of connections.

The thing that many people may not realize is that the biggest problem with the bandwidth provided in the US is that it is only limited because the big ISPs want it that way so that they do not have to pay to keep upgrading their equipment. After all they payed millions of dollars building their networks and burying cable everywhere that they want to milk every penny out of, even if they invested in a dead technology all because they felt better spending money on the old tried and true methods. Unless these BIG ISPs start really building up there networks and using more of their current line potential the US will keep falling further behind the world. Every home in the US should have had Fiber Optic by now at least that was what we were being told in the 90's when we were paying the big bucks just for 56k in the home but now I see they have pushed fiber optic for every business initiative to 2012 or later so having it in the home may be much later than that. The average home connection in Japan is between 30 and 90 Megabits/sec. The big cable companies have in many towns completely rewired the entire town just to keep up with customer demand for faster high speed but they are only trying to keep up not go above and beyond with there capabilities. Just think if they would have spent twice the money they did with the new coax and instead ran a bundle of fiber down every street so that every house had a direct connection to the closest company trunk and since fiber does not suffer the same level of degradation trunks could be consolidated and every house that wanted internet could be hooked up for a flat fee and get whatever speed they wanted to pay for up to the limit of that fiber coming into there house even several miles away from the closest town. Then the only thing that the cable company would have to focus on would be general line maintenance and upgrading there backbone to support their customer demand instead of the other way around. Since they are big enough odds are many are covering several states they could use there own networks to mesh and bridge the gaps that the country has in service.

Pricing should be set on a flat rate for a dedicated speed connection OR on a per Terabyte transfer of data with an unfiltered speed, regardless of whether the customer uses it or not the speed should be there. The whole idea of formulas is just created as a marketing scheme because the companies see that the average customer only used for example about 1/5 of his/her connection or less most of the time and so they figure why not put 3-4 other users on the same 3 meg connection and charge the same, well that is fine as long as everyone only uses there connection minimally but the minute you start having users who use there whole connection more due to online video and other services that are bandwidth hungry they start getting their connections filtered to keep the other customers happy and pissing off the one who is using what they payed for.

Now that's just an example and a normal big ISP would have maybe 1000 households on a 1Gbit/s connection with the idea that most people will only use a small portion of there lets say 6 or 10 meg connection and at varied times of the day. Now instead of improving there backbone they will keep changing there network on the client side by adding filters and throttling equipment to spread the bandwidth evenly, and filtering out bandwidth hogging content. If every household were to increase their normal load which is what is happening with the advent of online media that soon everyone's connection is slowing to a crawl and the ISP's try different ways of reducing the load through filtering rather than saying hey the formula that we use is no longer in line with today's use of the internet and we need to update our backbone and meanwhile all the customers are suffering through poor service and the ISP is still making more money and only a small percentage is going into the improvement of the actual service to keep up with the current and future demands.

The bandwidth is only truly limited by the funding necessary to create more and maintain it. Now because the big ISPs control the backbone the small ISPs have no choice than to lease there backbone from the large ISPs and so they can only stay competitive through careful planning and constantly changing there service as they get more customers that the big ISPs have no intention of servicing because it is not profitable enough for them in the short term.

So in my humble opinion the large ISPs are to blame for the US being so far behind and people are just looking for a way to get the service they are expecting as advertised but not delivered. However they are only hurting themselves if they get caught for it.
Berkelley · November 20, 2008 - 13:33 EST #9
America is a third world country what comes to information technology.

In here 100Meg line costs about 58$/month, and there is no throtting of any connection.

Not really useful to hack anything..
james · January 13, 2009 - 19:57 EST #10
America is full of nothing but corporate greed. I have cable internet, pay 65 dollars a month and am supposed to get 6 mb download and 365 kbs upload, but usually average anywhere from 2.5 mbs to 4.5 mbs download. I'm getting robbed by the cable company. THey are flat out stealing from me!!! So what makes it ok for them to steal but not ok for me to take advantage of something i purchased and am doing in my own home? Corporate greed can suck a fat one!!
Lee Bennett (ATPM Staff) · January 13, 2009 - 20:30 EST #11
James - hate to tell you this, but hardly anyone gets consistent speed at the maximum cable companies advertise, and it doesn't mean they're bilking you. There are a *lot* of factors to consider. It could be anything from the maximum speed uploads from whatever server you're pulling information from to problems with congestion outside of your provider's control. My cable service advertises up to 15mbps downloads, but realistically get 10-12. The top speed advertised is a possible speed under 100% perfect conditions with equipment and traffic, and I shouldn't have to tell you that conditions are essentially never 100%.

I'm not saying that cable internet companies are perfect angels. I do, in fact, believe they overcharge and should be offering much higher speeds to keep up with speeds available around the world. However, I don't think your actual speeds vs. advertised speed is very high on the list of my concerns.
FranciscoNET · February 7, 2009 - 03:25 EST #12
I live in New York City (to be more specific in the Bronx).

My cable provider (Cablevision) started advertising speeds of 6 MBit/s when I first signed up for their service about 5 years ago. Now doing a speed test I just got a 13.0MBit/s for downstream and 2.1MBit/s for Upstream which is not bad. AND I have the option to up the downstream to 24MBit/s if I decide to pay them 9 dollars more per month for their (Boost Plan), which by the way I had it about 4 months ago and I was getting an average speed of 17.4 MBit/s while my 24MBit/s "Boost Plan" was active, but my father decided to cancel it to save some money. Hey, I am only loosing about 4MBit/s without the boost plan which is still a very fast connection that gives me a good ping response time for my multiplayer progs/games and a non-laggering youtuve/video streaming experience and still able to download my favorite linux distribution ISO image in no time. Therefore, in my case, I dont have a valid reason to hack a modem to get a "good speed" since I am already getting a good speed. In fact, no one that I know in New York City hacks their cable modem. (It might be a totally different story in other states)

I think that New York City has the fastest ISP in the whole USA when I keep hearing stories about other ISP's in other states. Oh BTW, Verizon is slowly wiring sectors of New Jersey and New York with fiber optics of two speed plans (as of their first advertising speeds) of 15MBit/s and 30MBit/s (I think they may have a 3rd plan of 60MBit/s by now but I have not confirmed that). So since our main cable provider competitor is doing fiber optic we will see what decision will Cablevision take when it comes to fiber optic, most likely I see them doing it in the near future.
Craig Warren · May 25, 2009 - 05:28 EST #13
In maine here i have RoadRunner, and i purchased the RoadRunner Turbo w/ Powerboost, and advertised i have 16Mb/s connection, however realistically i have 21+Mb/s (with a max to date of 31.72Mb/s), and my provider lets me use my own zoom cable modem, its not hacked because i am VERY VERY much more then satisfied with my 60 dollar a month plan, especially when downloading a gig of files takes minutes not hours. :-D

For the people who are bitching about cable, yes the government isnt perfect, but its extremly hard to upgrade backbones when the demands keep going up, because they do not want to shut down customers or have rolling blackouts of internet, planning and execution of deployment is more money then anyone here probably realizes.

although i have a biased oppinion because of my internet, however hacking your modem is illegal because (believe it or not) the load balencing/filtering is a security measure to keep from overshooting their budget, its like using the energy saver function for home appliances example, and hacking around security measures is illegal.

In places with alot of people, such as new york or calif. the demand is growing more and more every day at faster rates. but as Dave K. said, we wouldnt have this problem with fiber optic.

Knowledge is power, however hacking to get around security measures is illegal.

Bangor, ME
James B · July 21, 2009 - 14:13 EST #14
I agree here with the idea that hacking an equipment which is not yours is illegal but I also agree with the idea that almost all the ISPs play the game speed vs bandwidth so one way or the other, if available, you have to pay extra money to get the best service.
I'm from Canada and my ISP is Cogeco. I'm currently testing their fastest residential package called ultimate and I'm getting 50Mbps down with 1.5Mbps up. I'm getting them 100% all the time so nothing to complain here. My problem is bandwidth to relate to the original OP. I only have 150 GB/m. With this speed you can get a very large file like 10 GB in 30 min so basically in 7.5 h your bdth is reached. From here it comes the frustration. Additional GB is $1 so if you don't pay attention to your traffic (only available the next day) you can pay big $$$. There is no bdth brick available like OK, you pay additional $25 for additional 50GB or $50 to go unlimited. It is ridiculous that after I'm paying $145/m then I still have to pay add traffic for that price. They know very well that the faster you go the more bdth you need. Rapidshare and Megaupload they sell traffic for close to 10-12c/GB so it is possible. In my case yes I'm fast but for my needs it's not enough. Options? There are none because they only focus on fast profit. After my knowledge a fast profit is not the key to a long success hence no investments in fiber optic or upgraded backbones.
Other options, yes. I've found after several phone calls a customer service rep that filled in a feedback/complaint form and we'll see. If in 1 month I don't get any positive answer then I'm going to change the package or the ISP. Do you call this progress because I don't.
James, Canada
Katrina · October 1, 2009 - 09:56 EST #15
I think every provider in canada does that- offers only so much bandwidth- Bell is only allowed to charge upto an additional $30 for bandwidth overages- But you have to be careful - if you use skype or Voip or other high usage sites - there is a stipulation in the agreement you sign stating that you give Bell permission to Charge you an undisclosed amount of money for going over what they deem "resonable usage"- and I have seen people's bills in the thousands of dollars........ pretty damn sad if you ask me.
basteredchild · November 8, 2009 - 19:34 EST #16
They cant find u if your ip address is just rolling numbers think about it people
PerfectEskimo · November 8, 2009 - 20:26 EST #17
right, think about the thousands of people every year picked up for cybercrime linked what people


your ip address...

read the news...maybe once...twice in your lifetime
mike james · January 19, 2010 - 17:51 EST #18
I have high spped internet and use a cable modem. My question is how do ISP providers turn the internet services on and off for non payment without going to the physcial address?

FranciscoNET · January 19, 2010 - 18:16 EST #19
Mike James, that question is easy. As you can see, every Cable Modem is assigned a MAC (Media Access Control) which is a hexadecimal value, that follows the following format:
Six sets of combination of twelve Characters/Integers. Each MAC address is unique to a specific hardware cable modem. When you turn on your cable modem, your MAC address must register to your Cable Modem's CMTS server, the CMTS server validates that your MAC address correspnds to a valid paid for service. As soon as you stop paying your bills, all what the Cable CO have to do is turn off your MAC address and their goes your access offline/walled gardened.

Cable Modems utilizes a system called DOCSIS Version 1.1 and Version 2 on some areas as a very strict way of going thru the chain of process of validating your MAC address and registering your cable modem on their network in such a trusted way that the user can't tamper with (of course hackers have had a great success hacking some cable modems, but that procedure is so complicated that most users aren't gong to try that making Docsis very effective still)

So, that's how Cable Companies can turn off your service without having to come physically to your house.

For your info, Cable modems is not the only device with MAC addresses, virtually all networking devices got their own mac addresses, such as the network card in your computer/laptop, wireless adapters, and routers all got their own unique MAC address, but these systems doesn't use the DOCSIS system. That is the reason why you have to power off/on your cable modem each time you change from one computer to another because you are changing to another input MAC address, but users are able to get by that problem installing a router since when you install a router all what your cable modem sees is ONE MAC address, one computer, even if you have 10 computers in your LAN side. For users where cable companies ties your MAC address to their systems, all what you have to do is clone your computer's MAC address to your router and then you can have more computers sharing the same cable modem connection.

I hope this answers yours and many other users questions.
J D · March 31, 2010 - 17:17 EST #20
The providers should change their business models entirely! They wack you for the most money possible instead of trying to keep it affordable to more people creating a larger customer base. $99.00 a month for the first year only to have it go up %50 the second year, followed by a normal 3-5% increase every year there after.....
rplatter · July 27, 2011 - 22:47 EST #21
It seems the venom in some of the previous posts is hampering the discussion.

The way I see it is:
If you sign a contract with an ISP for a certain level of performance you should get that level of performance when you need it. However, most ISP's have an 'up to' clause in their contract saying, in effect or blatantly, that you might not get that speed depending on what your neighbors are doing. Basically what you are doing is sharing the cost of a large pipe with your neighbors. Each neighbor pays a part of the whole cost(with a little more going to the ISP for managing the whole thing) and everyone shares it. If you are hogging the shared bandwidth you are causing a problem. Similar to you shutting down your street to throw a party without the neighbors permission.

On the other side. I should have the right to modify equipment I own to do what I want. For my part, I want to have the Modem provide additional services that it won't/can't natively. Just because I want to play with the innards of the cable modem does not make me a thief and painting me with that brush is liable. Until and unless I actually use more of the bandwidth than I am paying for or I interfere with my neighbors use, I am well within my rights to do whatever I want to the equipment I own.
Primarily I do not want to have to pay for an additional device (Router) to allow more than one computer to access the internet concurrently. This should be built into the cable modem. As should some level of firewall. I want to add that functionality to the cable modem I own.

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