This was exactly what DNS over HTTPS was supposed to prevent.

Comcast has agreed to be the first home broadband internet provider to handle secure DNS-over-HTTPS queries for Firefox browser users in the US, Mozilla has announced.

This means the ISP, which has joined Moz’s Trusted Recursive Resolver (TRR) Program, will perform domain-name-to-IP-address lookups for subscribers using Firefox via encrypted HTTPS channels. That prevents network eavesdroppers from snooping on DNS queries or meddling with them to redirect connections to malicious webpages.

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At some point in the near future, Firefox users subscribed to Comcast will use the ISP’s DNS-over-HTTPS resolvers by default, though they can opt to switch to other secure DNS providers or opt-out completely.

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Incredibly, DNS-over-HTTPS was heralded as a way to prevent, among others, ISPs from snooping on and analyzing their subscribers’ web activities to target them with adverts tailored to their interests, or sell the information as a package to advertisers and industry analysts. And yet, here’s Comcast providing a DNS-over-HTTPS service for Firefox fans, allowing it to inspect and exploit their incoming queries if it so wishes. Talk about a fox guarding the hen house.

ISPs “have access to a stream of a user’s browsing history,” Marshall Erwin, senior director of trust and security at, er, Mozilla, warned in November. “This is particularly concerning in light of the rollback of the broadband privacy rules, which removed guardrails for how ISPs can use your data. The same ISPs are now fighting to prevent the deployment of DNS-over-HTTPS.”

Comcast is pinky swearing that it won’t misuse the data, which means about as much as their statement about when their service tech is supposed to show up.