Manual installation of the security certificate into the Firefox browser

Different versions of Firefox browser require different approaches for AdGuard to perform HTTPS filtering. Most of the time this happens in Firefox versions older than v81.1.1. To solve this issue, try Method 1 described below (it works with nightly– and beta–versions of the browser).

Enabling access to certificates installed on device

Method 1 (Certificate located in the User store)

This method will only work in Beta or Nightly versions of the browser, as regular versions of Firefox don't have about:config anymore.

To make Firefox trust user certificates, you need to toggle the hidden option in the browser itself:

  1. Run the browser;
  2. Navigate to about:config page;
  3. Type root in the search field;
  4. Locate the option security.enterprise_roots.enabled and toggle it, making it true.

Method 2 (Certificate located in the System store)

This method will only work on rooted devices.

  1. Install and configure adb;

    On the Windows platform, Samsung owners may need to install this utility.

  2. Activate the developer mode and enable USB debugging:
    • Open the Settings application on your phone;
    • Go to System section (last item in the settings menu). In this section find sub-item About phone;
    • Click on the Build number line 7 times. After that, you will receive a notification that You are now a developer (If necessary, enter an unlock code for the device);
    • Open System Settings > Developer Options > Scroll down and enable USB debugging > Confirm debugging is enabled in the window Allow USB debbuging after reading the warning carefully.
  3. Install the Firefox browser (release version);
  4. Open the AdGuard settings > Network > HTTPS Filtering > Install the certificate in Firefox > INSTALL FOR OLD VERSIONS;
  5. Open the folder data/data/org.mozilla.firefox/files/mozilla using adb shell su and cd data/data/..., then browse to the folder named xxxxxxx.default and memorize its name;
  6. In the specified folder we are interested in two files:
    • cert9.db
    • key4.db
  7. We need to move these files to a folder of the browser where the security certificate issue occurred:
    • data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyy.default.
  8. The full сommand will look like this:
    • adb shell su
    • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxxx.default/cert9.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.
    • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxxx.default/key4.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.

In case you received the system notification permission denied, you should first move the specified files to the permission-free directory. And after that you should move them to the necessary folder in your Firefox browser.

The full command should look something like this:

  • adb shell su.
  • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxx.default/cert9.db sdcard/Download
  • cp -R data/data/org.mozilla.firefox/files/mozilla/xxxxxxxxx.default/key4.db sdcard/Download
  • cp -R sdcard/Download/cert9.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.
  • cp -R sdcard/Download/key4.db data/data/org.mozilla.<browser_name>/files/mozilla/yyyyyyyyyy.default.

If adb shell su does not work, you should try adb shell initially, and then su.