I first learned about the Public Hotspot feature a year ago when I wrote about the Comcast modem I had and what a security nightmare it was. Since then I have owned and tested roughly 12 Comcast provided modems before finally purchasing my own. Public Hotspot enables users with XFinity modems to broadcast a second wifi signal, this signal can be picked up by other Comcast customers and joined for wifi anywhere they go. A few days ago this feature was enabled for 50,000 Comcast customers in Houston, Texas and will be enabled for millions of homes across the country by the end of the year according to Comcast.
Comcast has been replacing older modems with their new all-in-one boxes for a few years now. These little black towers usually manufactured by Arris and Technicolor have built-in wifi capabilities, allow connection of phones and faxes, have a battery backup and a firewall. Wifi is on by default and all a user has to do to join is connect to the preset network with a password that is on a sticker on the back or bottom of the modem. No other settings have to be tweaked, it’s connect and enjoy your internet/phone. The public hotspot feature will be enabled remotely by Comcast, you don’t have to do anything and may not even be aware of it happening.
My XFinity modem was an Arris and after writing about it a year ago I started doing a few tests. One of these tests was to see if wifi was really disabled when Comcast support told me it was. Turns out, it wasn’t. I found it dodgy that I could not disable wifi myself, I had to call Comcast support to have it done. Why would I not be allowed to disable wifi myself? Once Comcast disabled the built-in wifi I noticed the little wifi light on the front of the modem turned off, this means the wifi is disabled according to Comcast. I grabbed an RF meter and reading were off the charts! It was not my AirPort Extreme because it was off, it was not my house phone because I turned that off, same for cellphones, bluetooth devices and wifi on the computers. There was no source of RF radiation in my house. Yet here it was a strong wifi signal pumping out of my modem that blanketed the entire house. I could faintly pick up the neighbors cordless phones and wifi routers and the smart meter outside was quite strong too but this signal was by far the strongest. I unplugged the modem and the signal kept going, I pulled the battery from the modem and finally the signal stopped.
I called Comcast and they assured me wifi was off. I asked them if it may be the public hotspot feature (I saw no other explanation) but they said that feature had not been activated in my area yet. I scanned the wifi bands and found no networks I could join yet the signal was there and it was stronger than my AirPort Extreme when it’s enabled. Comcast had no explanation so they sent me a new modem. The new modem had the same issue. I went through 7 modems and they all had the same issue. Then modem 8 arrived and once wifi was disabled there was no rogue signal. This was a Technicolor model TC8305. However the modem dropped the connection several times a day and would take hours to reconnect after a power drop (the Technicolors do not come with a battery whereas the Arris models do). Comcast support admitted the Technicolors are a nightmare with their wonky firmware and changing a single settings usually requires multiple restarts or resets. So modem 9 was sent which was an Arris and of course had the same rogue signal issue. Modem 10 was another Technicolor (no rogue signal) but was worse than the first, it bricked completely after Comcast tried to change a setting. Modems 11 and 12 were Technicolors (models TC8305 and TC8305C) which functioned so poorly I gave up and purchased my own modem instead. A modem I have complete control over, doesn’t have built-in anything that can go rogue on me and takes up a lot less space. A Motorola SURFboard eXtreme Cable Modem SB6141. The Comcast provided modems also re-enabled wifi after a reboot or if unrelated settings were changed.
I have several reasons not to trust Comcast but this rogue wifi signal business was it for me. Now they started enabling the public hotspot feature and though they tell people it is secure and won’t impact your speed, I do not believe it. I guess time will tell. The wifi is generated by the same hardware box as your own wifi (if you use XFinity’s preset wifi) so access to that public wifi means access to your modem. I can think of a few scenarios where this can go wrong and as more homes have this public signal enabled it will become easier for those with ill intent to start poking and prodding at it until a vulnerability is found. Also, this signal may interfere with your own wifi, impacting range and or speed. Not to mention this will be a nightmare for those that are sensitive to RF radiation and/or simply want to stay away from wifi for health reasons.
You can disable the public hotspot feature by following the steps posted here. If it will truly be disabled and stay disabled I don’t know, you’ll have to check with an RF meter to be sure. You certainly can’t take their word for it is what I have found.