You're paying AI companies a monthly subscription fee to be fingerprinted like a parolee.

I got bored and ran uBlock across Claude, ChatGPT, and Gemini simultaneously.

Claude:

  • Six parallel telemetry pipelines.
  • A tracking GIF with 40 browser fingerprint data points baked into the URL, routed through a CDN proxy alias specifically to make it harder to block.
  • Intercom running a persistent WebSocket whether you use it or not.
  • Honeycomb distributed tracing on a chat UI because apparently your conversation needs the same observability stack as a payments microservice.

ChatGPT:

  • proxies telemetry through their own backend to hide the Datadog destination URL from blockers.
  • uBlock had to deploy scriptlet injection — actual JS injected into the page to intercept fetch() at the API level — because a network rule wasn't enough.
  • Also ships your usage data to Google Analytics. OpenAI. To Google. You cannot make this up.
  • Also runs a proof-of-work challenge before you're allowed to type anything.

Gemini:

  • play.google.com/log getting hammered with your full session behavior, authenticated with three SAPISIDHASH token variants, piped directly into the Google identity supergraph that correlates everything you've ever done across every Google product since 2004.
  • Also creates a Web App Activity record in your Google account timeline. Also has "ads" in one of the telemetry endpoint subdomains.

When uBlock blocks Gemini's requests, the JS exceptions bubble up and Gemini dutifully tries to POST the error details back to Google. uBlock blocks that too. The error messages contain the internal codenames for every upsell popup that failed to load.

KETCHUP_DISCOVERY_CARD.
MUSTARD_DISCOVERY_CARD.
MAYO_DISCOVERY_CARD.

Google named their subscription upsell popups after condiments and I found out because their error handler snitched on them.

All three of these products cost money.
One of them is also running ad infrastructure.

Touch grass. Install @ublockorigin

#infosec #privacy #selfhosted #foss #surveillance

@k3ym0 @ublockorigin Fascinating and worrisome. For the less technically adept… would uMatrix be as effective? Or are these specific capabilities of uBO?

@QuercusMacrocarpa @ublockorigin uMatrix is unfortunately abandoned — development ended in 2021, same developer as uBlock Origin, he just stopped. there's also an unpatched vulnerability in it so I'd avoid it at this point.

uBlock Origin in medium mode covers most of what uMatrix used to do for this specific threat — it blocks third party scripts and XHR requests by default which is exactly what catches the telemetry pipelines I documented.

one important caveat though: if you're on Chrome, uBlock Origin was gutted by Google in late 2024 as part of their Manifest V3 changes. the full version no longer works on Chrome. for real protection you need Firefox or Brave with uBlock Origin installed. which, honestly, is probably worth a separate post.

@k3ym0 @QuercusMacrocarpa @ublockorigin

one important caveat though: if you're on Chrome, uBlock Origin was gutted by Google in late 2024 as part of their Manifest V3 changes. the full version no longer works on Chrome. for real protection you need Firefox or Brave

OR UngoogledChromium uBlock from
https://github.com/gorhill/uBlock/releases

Add localcdn or privacy Badger.

Do not use googles store, it is a pernicious tracker... and

Releases · gorhill/uBlock

uBlock Origin - An efficient blocker for Chromium and Firefox. Fast and lean. - gorhill/uBlock

GitHub

@Kerplunk @k3ym0 @QuercusMacrocarpa @ublockorigin

We're building an open-source, system-wide ad-blocker called Zen.

It sits outside the browser, so it's unaffected by the artificial limitations of Manifest V3 (among other benefits), so I'd recommend it to anyone still using Chrome.

We're aiming for 100% feature parity with uBO and other ad-blockers (already 90% there). Check it out if you're interested: https://github.com/ZenPrivacy/zen-desktop

GitHub - ZenPrivacy/zen-desktop: Simple, free and efficient ad-blocker and privacy guard for Windows, macOS and Linux.

Simple, free and efficient ad-blocker and privacy guard for Windows, macOS and Linux. - ZenPrivacy/zen-desktop

GitHub

@anfragment @Kerplunk @QuercusMacrocarpa @ublockorigin this actually looks pretty interesting.

Looks like it’s essentially a local-run explicit web proxy doing MiTM/TLSI?

@k3ym0 @Kerplunk @QuercusMacrocarpa @ublockorigin

Exactly. It sets up a local MITM proxy, inspects the request/response flow, blocks or modifies requests, and also injects custom CSS and JS into pages to emulate features that would normally require browser extension APIs.

To preempt the question - all proxying is local. The app has to install a root CA, but it's generated on-device and doesn't leave it.

@anfragment @Kerplunk @QuercusMacrocarpa @ublockorigin looks like you’re allow-listing OpenAI in zen-https-exclusions/common.txt (line 117/118)?

Wouldn’t that mean that it wouldn’t provide protection while using ChatGPT via browser?

Don’t get me wrong, I think it’s a wonderful idea, and your implementation actually looks very solid, but it doesn’t look like it would protect privacy within the context of my original post (unless I’m misunderstanding something, in which case please do correct me and tell me to RTFM or GTFO).

@k3ym0 @Kerplunk @QuercusMacrocarpa @ublockorigin

We added those exclusions because the desktop ChatGPT app complains loudly about MITM, and we'd rather avoid people disabling Zen completely out of frustration.

On the telemetry endpoints: thank you for flagging ab.chatgpt.com - I've added a scriptlet similar to uBO's to our filter list and the requests are now blocked: https://github.com/ZenPrivacy/filter-lists/commit/1a1b3c045138abc66d0b47a900f9ed071461d244

Requests to GA were blocked already. Going through other ones in the original post as well.

@k3ym0 @Kerplunk @QuercusMacrocarpa @ublockorigin

Also, just to clarify - the exceptions control hosts traffic TO which gets allowlisted. Outbound requests FROM an allowlisted host still get filtered through Zen.

@anfragment @Kerplunk @QuercusMacrocarpa @ublockorigin I saw your PR! Thanks so much for tagging me - you're a legend :)

Honestly I stumbled across it by mistake bc I was curious how you handle exemptions.

At this point I just want to know how I can help support what you're doing :)

@k3ym0 @Kerplunk @QuercusMacrocarpa @ublockorigin

Thank you! Dropped you a message on Signal.