[Comcast] announced this week that it is rolling out Xfinity Shield, a cyber and home protection platform available to millions of customers [with an Advanced Xfinity Gateway] nationwide at no extra cost. The service bundles cybersecurity and parental controls with WiFi Motion, a feature that can turn existing WiFi equipment into motion detectors.
“An opt-in feature, WiFi Motion uses the WiFi signal from a customer’s Xfinity Gateway to sense movement in their home — no cameras needed or recordings captured,” the company wrote in a press release.
Comcast says that WiFi Motion works by detecting changes in the radio frequency signals traveling between routers and WiFi-connected devices.
This piece turned into a rabbit hole. Much as Wi-Fi–based motion detection sounds like science fiction, it’s not new. Home monitoring is the first use case suggested by the Wireless Broadband Alliance in its introduction to Wi-Fi sensing, the umbrella term for using Wi-Fi signals in a radar-like fashion. Both that introduction and Comcast’s materials about Xfinity Shield claim that Wi-Fi sensing offers more privacy than cameras or other sensors, which is probably true, but neither acknowledges that Wi-Fi sensing introduces its own privacy concerns and a certain creepiness factor.
Although Comcast says that WiFi Motion captures only motion activity and does not identify individuals, that’s a choice, not an inherent technology limitation. Earlier this year, German researchers demonstrated that Wi-Fi signals could identify specific individuals with 99.5% accuracy. Plus, since Comcast stores motion event data in its cloud systems, it’s available to law enforcement and court orders.
Realistically, Comcast’s WiFi Motion feature probably isn’t a huge privacy problem on its own. But I’m uneasy about the broader privacy question around Wi-Fi sensing. I don’t have the background or expertise to evaluate the claims in this blog post from Pascal Piron, but he says the 802.11bf working group analyzed the privacy concerns but failed to agree on what to do, so the standard shipped without any mitigation. (Comcast’s feature reportedly uses a proprietary technology from Cognitive Systems instead.) However, research suggests that privacy is being taken seriously for 6G cellular, where similar issues crop up. With luck, the efforts in the 6G cellular world will bleed over to the Wi-Fi world before it becomes a problem.
Comcast Xfinity may be the first broadband provider to include “Wi-Fi Sensing” technology in its branded routers, but the technology started appearing as long ago as 2019 in third party devices.
As far as I can tell, Linksys was first-to-market with its “Linksys Aware” subscription service on some Velop systems, though Linksys discontinued it in 2024. Nonetheless, Wi-Fi Sensing will be part of the IEEE 802.11bf standard, so you can expect it to become ubiquitous. In addition to routers, stationary devices like smart speakers and thermostats can be used in Wi-Fi Sensing networks.
At this writing, the Xfinity support article that @ace linked includes the following Xfinity-branded devices as being compatible with “WiFi Motion”:
TXB7 (Only includes XB7 models manufactured by Technicolor.)
XB8
XB9
XB10
MXB1
XER10
The wording of the Xfinity support article implies that aside from the Technicolor-manufactured TBX7, the other listed routers include support for WiFi Motion, regardless of manufacturer. Photos and descriptions of the included models are below.
When I had Comcast at my business, they required that I use their cable modem/WiFi router. It was garbage, so I had them configure it as a bridge and turn off the radios (that wasn’t a feature that the end-user was permitted to access). Several times during the two years or so that I had the service, they remotely re-enabled the radios which wreaked havoc with my office by interfering with the WiFi that actually worked.
So, with the WiFi radios disabled, you wouldn’t have to worry about motion detecting, but I wouldn’t trust that Comcast wouldn’t remotely re-enable the radios without notice.
Similarly, when I had Comcast Business service at my home, they started illegally intercepting my DNS traffic and re-directing it to their own, poisoned servers which interfered with (among other things) the ability of my mail server to look up DNS block lists. They called this a security product to which I had subscribed, but I had not done so.
Again, I could spend hours on the phone and eventually “opt out” of a service to which I had explicitly never opted in, but then some weeks later they would re-enable it and I’d have to go through the whole process again. Eventually, they made it a user option in their modem firmware, but they would still turn it on occasionally without notice or consent.
I personally would have no confidence that Comcast would refrain from enabling WiFi Motion without consent, opt-in or not. Nor would I trust that Comcast won’t store the motion data in a public or easily breached database.
Comcast offered this service to me as a home security feature about a year ago (maybe it was still in Beta). I tested it and it seemed to work, but ultimately I decided that the hassle of a false positive when I was away from home (especially if on vacation) would offset any “peace of mind” that I would get from knowing that nothing was moving in my house when I wasn’t there. If I get a notification that the system detected movement when no one is supposed to be in the house, what are my options? Bother a neighbor to check on the house and possibly find nothing, or worry about it until I get back home and find out nothing is amiss. It seems like enough information to cause concern, but not enough to be useful. No thank you.
I wonder if Comcast offers this to the operators of “senior communities”. A family member lives in a facility that has motion detection in each of its apartments. The facility uses Comcast for the TV, WiFi, and Internet in each unit. There aren’t any dedicated motion detectors that I’ve been able to find but there is a small, unmarked box directly connected to the Comcast modem-WiFi unit. Supposedly (I’ve only heard this second hand) this box is related to motion detection throughout the entire unit. There also is some sort of networked device mounted on the ceiling of the unit that doesn’t seem to have anything to do with the TV or WiFi service.
I’ve been with Comcast/XFinity for a number of years, and have always had my own modem and router (currently have Netgear devices). They have not sent me anything about this, and I would not even consider it, especially with the issues Adam pointed out.