Cable modems susceptible to packet sniffing or similar?

[ppdes]

We all hear about cable modems sharing bandwidth. Does that also mean that everyone gets your signal in some way and can do the equivalent of packet sniffing?

 

[MustISO]

I'm not aware of that being possible with the way the system is setup.

 

[ScottMac]

Each user is in essentially a VPN between the home and the aggregate point within the (secure) provider's network.

Further, the Ethernet traffic is encoded in one of a number of ways (depending on the system) such that you would need a protocol analyzer specific to that encoding, in order to capture the (encrypted) traffic to try and break/decrypt it.

It's not impossible , but it's not likely (to an extreme degree). Do keep in mind that the government has the keys to all of the "legal" encryption and can look at anything it can justify (probably cause, reasonable suspicion).

 

[tranceport]

I've sniffed on my cable modem plenty of times. I never see anyone's traffic but mine and broadcasts.

 

[ViRGE]

Originally posted by: ScottMac
Each user is in essentially a VPN between the home and the aggregate point within the (secure) provider's network.

Further, the Ethernet traffic is encoded in one of a number of ways (depending on the system) such that you would need a protocol analyzer specific to that encoding, in order to capture the (encrypted) traffic to try and break/decrypt it.

It's not impossible , but it's not likely (to an extreme degree). Do keep in mind that the government has the keys to all of the "legal" encryption and can look at anything it can justify (probably cause, reasonable suspicion).

It's my understanding that Baseline Privacy is fairly weak encryption, using 56bit DES. DES is amazingly weak, and we (Team AnandTech Distributed Computing) were breaking DES in under a day with hardware that probably costs less than $10k these days. So while it's not trivial to crack DES, it's easy enough that anyone that wants to take the time and has the skills, can do so for fairly cheap. It's secure enough to keep out the casual hackers looking to break in, but it won't stop anyone who is committed.

Of course anything not sent via an encrypted protocol (HTTPS and the like) should be considered fully insecure, so I suppose it's a bit of a moot question.

 

[Modelworks]

You can intercept someone else cable connection by using cloning. Its a matter of fooling the provisioning server into thinking you have the same modem as the one that you want the data from.
It is not common because most cable operators have put in safeguards to prevent it. Like only allowing the modem to be provisioned once. The problem before was that even if they did put in that safeguard they sometimes did not link the provisioning servers or they were updating slowly allowing two modems to get the same provisioning information.

Just google modem cloning and you can find all the information you need.
Most of it is irrelevant now but its still a good read.

Once you have the same provisioning its easy to get the other persons data.

 

[VirtualLarry]

Originally posted by: Modelworks
You can intercept someone else cable connection by using cloning. Its a matter of fooling the provisioning server into thinking you have the same modem as the one that you want the data from.
It is not common because most cable operators have put in safeguards to prevent it. Like only allowing the modem to be provisioned once. The problem before was that even if they did put in that safeguard they sometimes did not link the provisioning servers or they were updating slowly allowing two modems to get the same provisioning information.

Just google modem cloning and you can find all the information you need.
Most of it is irrelevant now but its still a good read.

Once you have the same provisioning its easy to get the other persons data.

I assume that you have to be on the same physical node as the one that you want to sniff too, right?

 

[spidey07]

Originally posted by: VirtualLarry
I assume that you have to be on the same physical node as the one that you want to sniff too, right?

What do you mean by "node"?

The encryption and key exchange is done between the modem and the CMTS.

 

[JackMDS]

Unlike DSL that comes in on your own private Tel. line the Cable systems work with nodes.

As an example one fiber comes to a building and from their a Coax goes to each floor and to individual feeds, but they are all together on the same node (no private cables beside from the door step into the Office/Apt.).

So in theory all the traffic is available at at any point within the node.

I say in theory cause (as an example) RR systems are used in big apartment, office, and combo buildings all over Manhattan. In my building alone there about 50 buseinesses and 250 apts., many of them are using RR Internet servie and need to be secure.

I doubt that it is so "Easy to Listen" as described above by few members.