Can a cable modem itself have a virus

cujo_77

Honorable
Mar 17, 2013
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10,510
I wanted to know if a virus can actually reside in a cable modem and infect a PC. I work in a law office and we keep a few computers off the network for security issues. The situation is I just reformatted a PC, re-installed the OS (Windows XP) and I am about to hook it to the internet to download all the needed updates. Like most small offices we have a cable modem connected to a wifi router that most people in the office use for tablets, cell phones, etc. All these things are personal items and have the ability of contracting virus because of all the internet browsing they do at home, coffee shops, etc. What I figured I would do is disconnect the modem from the router and then hook it directly to the PC then download the updates. I planned on rebooting the modem so nothing is stuck in its memory, but I just wanted to know if I went ahead with the plan above is there any risks of a virus being passed onto the PC that I am updating?

P.S. I have the standard Motorola "Surfboard" cable modem SB5101U
 

john-b691

Honorable
Sep 29, 2012
703
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11,160
No the modem itself cannot get a virus but using ONLY the modem you expose your PC you are patching directly to the internet. You are likely at less risk from the items in the office than internet. Not a big risk either way I suspect.

You would be better off connecting to your router and disabling the wireless and unplugging other devices. The router will act as a partial firewall because of the NAT. Since traffic coming to a nat router from someone in the internet must be manually port forwarded to a real machine the router will just discard it if it can't figure it out.