Every time the browser is started, uBlock Origin connects to an external server without asking the user

[dsh4dtw]

Prerequisites

• I verified that this is not a filter issue
  • Filter issues MUST be reported at filter issue tracker
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uBlockOrigin
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported
• The issue is not present after wholly disabling uBlock Origin ("uBO") in the browser
  • If the issue is still present after wholly disabling uBO in the browser, then the issue is unrelated to uBO
• I tried to reproduce the issue when...
  • uBO is the only extension
  • uBO with default lists/settings
  • using a new, unmodified browser profile
• I checked the documentation to understand that the issue I report is not a normal behavior

Description

uBlock Origin automatically connects to external servers each time the browser is started without asking the user.

A specific URL where the issue occurs

These are the external servers that uBlock Origin connects to each time the browser is started.

• d2nxq2uap88usk.cloudfront.net
• content-signature-2.cdn.mozilla.net

Steps to Reproduce

1. Install uBlock Origin locally for the first time and add all the lists you want locally. Disable Auto-Update filter list under Filter lists.
2. Exit the browser
3. Connect to an internet connection
4. Start the browser
5. uBlock Origin will automatically connect to external server without asking the user
6. There is easy way for user to disable this behavior

Expected behavior:

If users have everything installed locally and all options disabled in the UI that are not local options, then uBlock Origin must not automatically connect to external servers without asking the user.

Actual behavior:

uBlock Origin automatically connects to external servers without asking the user.

Your environment

• uBlock Origin version: 1.36.0

• Browser Name and version: Customized Firefox 89.0.1, which is designed to behave as expected. That is, everything that the user would generally see in the UI is designed so that you know it's a local option or an option that requires an internet connection. There are no hidden background servers or invisible options that are not displayed in the UI.

• To summarize:
  By default, my customized Firefox version does not connect to any external server.

• Operating System and version: Linux Kernel 5.12.12 and customized desktop environment

[uBlock-user]

content-signature-2.cdn.mozilla.net

Firefox connects to this server to authenticate extensions signature with their server, not uBO.

d2nxq2uap88usk.cloudfront.net

CNAME of content-signature-2.cdn.mozilla.net, so this is from Firefox.

[gorhill]

Install uBlock Origin locally for the first time

What does "locally" mean? How exactly did you install uBO?

add all the lists you want locally

And what are those "all the lists"? How are they "added"? Provide details otherwise there is nothing which can be investigated.

If you subscribe to filter lists which are not part of the package, uBO will have to fetch them from the server on which they are hosted if you want them enforced.

Connect to an internet connection

Was there an internet connection when you added "all the lists"?

[gorhill]

content-signature-2.cdn.mozilla.net

That's not uBO, it's Firefox probably verifying the signature.

[dsh4dtw]

You are both right, I have tried several times and since I disabled uBlock Origin, this server still exists. So it is a Firefox problem after all.

I then found a possible bug.

uBlock Origin Settings -> Reset to default settings...

Whenever I click on this function, it always appears that it automatically connects to this external server -> easylist.to. Can you reproduce it on your site?

[gorhill]

host content-signature-2.cdn.mozilla.net
content-signature-2.cdn.mozilla.net is an alias for d2nxq2uap88usk.cloudfront.net.

[gorhill]

Whenever I click on this function

This resets to default settings, and hence auto-update is reset to being enabled, and beside, you still do not provide which lists are enabled -- not all lists are part of the package, for instance none of the regional ones.

[gorhill]

@dsh4dtw

• The issue is not present after wholly disabling uBlock Origin ("uBO") in the browser

Then:

You are both right, I have tried several times and since I disabled uBlock Origin, this server still exists.