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Wow. How could Comcast control the firmware updates for a product they didn't make? Did they hijack the update software lookup? This must have been done with M

Wow. How could Comcast control the firmware updates for a product they didn't make? Did they hijack the update software lookup? This must have been done with Motorola's backing.

ohazi 12y ago
So I looked into this a while ago and wasn't really able to find an authoritative answer. Farthest I got was here: http://forums.comcast.com/t5/Home-Networking-Router-WiFi/DOCSIS-3-0-Modems/td-p/778147 http://forums.comcast.com/t5/Home-Networking-Router-WiFi/DOC... The claim seems to be that Comcast has the ability to update the firmware of any modem that is physically connected to their network. I don't know if this is actually true. There might be some obscure part of the DOCSIS spec (or an extension) that specifies how firmware updates can be delivered from the coax side (if so, I've certainly never been able to find it, and I don't even want to think about what they're (not) doing for security and authentication). If this claim is true, then the best you can do is to get a dumb "modem only" device, in order to minimize their control of your hardware and network. Use your own router and/or your own wireless gateway and maintain exclusive firmware control over those devices. If the claim is false, then they're likely able to get in via some sort of Comcast-specific protocol. This protocol might be in the generic firmware because Comcast also happens to sell this particular device themselves, and maintaining a single firmware image is probably easier for Motorola logistically. I wonder if there are similar update channels for other ISPs on the same device.
- hackmiester 12y ago
  I believe it's pretty common for the customer equipment to be updated by the ISP. I have an old modem-only Scientific Atlanta modem. If I start it up on Comcast, the web GUI gets rebranded to Cisco, who now own SA. If I start it on WideOpenWest, it isn't rebranded anymore, it says Scientific Atlanta on the web GUI again.
  - uxp 12y ago
    For DOCSIS modems, they are only updatable and configurable via the ISP. When you connect and power on your cable modem, it requests a configuration file from someplace upstream. That config file contains the firmware version that is compatible with both the network and the modem, and if they don't match then it'll either ask upstream for a new firmware image or fail to connect to the network. Any configuration done by an end user is limited to the LAN portion of the network. WAN should be cut off entirely.
- leorocky 12y ago
  This all makes sense, but if you get a modem with no wifi capabilities they can't turn your personal network into a wifi hotspot even if your ISP can update the firmware on the modem.

Wow. How could Comcast control the firmware updates for a product they didn't make? Did they hijack the update software lookup? This must have been done with Motorola's backing.

ohazi 12y ago

So I looked into this a while ago and wasn't really able to find an authoritative answer. Farthest I got was here: http://forums.comcast.com/t5/Home-Networking-Router-WiFi/DOCSIS-3-0-Modems/td-p/778147 http://forums.comcast.com/t5/Home-Networking-Router-WiFi/DOC... The claim seems to be that Comcast has the ability to update the firmware of any modem that is physically connected to their network. I don't know if this is actually true. There might be some obscure part of the DOCSIS spec (or an extension) that specifies how firmware updates can be delivered from the coax side (if so, I've certainly never been able to find it, and I don't even want to think about what they're (not) doing for security and authentication). If this claim is true, then the best you can do is to get a dumb "modem only" device, in order to minimize their control of your hardware and network. Use your own router and/or your own wireless gateway and maintain exclusive firmware control over those devices. If the claim is false, then they're likely able to get in via some sort of Comcast-specific protocol. This protocol might be in the generic firmware because Comcast also happens to sell this particular device themselves, and maintaining a single firmware image is probably easier for Motorola logistically. I wonder if there are similar update channels for other ISPs on the same device.

hackmiester 12y ago
I believe it's pretty common for the customer equipment to be updated by the ISP. I have an old modem-only Scientific Atlanta modem. If I start it up on Comcast, the web GUI gets rebranded to Cisco, who now own SA. If I start it on WideOpenWest, it isn't rebranded anymore, it says Scientific Atlanta on the web GUI again.
- uxp 12y ago
  For DOCSIS modems, they are only updatable and configurable via the ISP. When you connect and power on your cable modem, it requests a configuration file from someplace upstream. That config file contains the firmware version that is compatible with both the network and the modem, and if they don't match then it'll either ask upstream for a new firmware image or fail to connect to the network. Any configuration done by an end user is limited to the LAN portion of the network. WAN should be cut off entirely.
leorocky 12y ago
This all makes sense, but if you get a modem with no wifi capabilities they can't turn your personal network into a wifi hotspot even if your ISP can update the firmware on the modem.