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I have Fiddler installed on my machine. I have installed the Fiddler Root Certificate to decrypt HTTPS traffic, but it only works in FF and IE, not in chrome. Chrome does not trust Fiddler's certificate and does not allow me to connect to any tunneled connections.

I tried looking on Fiddler2.com's page for a plugin but I don't see anyhing.

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  • What specifically did you end up doing? By default, Chrome respects the same Windows-wide certificate store used by IE. Firefox has its own store and requires manual configuration.
    – EricLaw
    Commented Apr 24, 2013 at 21:52
  • When attempting to import your cert in the "Manage Certificates" modal, are you on the "Authorities" tab? (I started out trying to import my cert in the "Your Certificates" tab, but that failed repeatedly. You need to be in the "Authorites" tab.)
    – Jellicle
    Commented Aug 20, 2013 at 15:25

5 Answers 5

Reset to default
175

I updated Fiddler and ran into a similar issue. This fixed it for me: http://textslashplain.com/2015/10/30/reset-fiddlers-https-certificates/

Fiddler 1.3.0+ (This is the new build and comes after 4.6.1.5+)

  • Click Settings (the cog in the top right hand corner).
  • Select the HTTPS tab from the left hand panel
  • Click Trust root certificate
  • Accept all prompts
  • You may need to restart Fiddler

Fiddler 4.6.1.5+

  • Click Tools > Options.

  • Click the HTTPS tab.

  • Ensure that the text says Certificates generated by CertEnroll engine.

    (Note: You may notice that it's not possible to change the engine from MakeCert to CertEnroll, in such case restart Fiddler and start from the beginning, it should show CertEnroll then.)

  • Click Actions > Reset All Certificates. This may take a minute.

  • Accept all prompts (to remove and re-add certificates)

Fiddler 4.6.1.4 and earlier

  • Click Tools > Options.
  • Click the HTTPS tab.
  • Uncheck the Decrypt HTTPS traffic checkbox.
  • Click the Remove Interception Certificates button. This may take a minute.
  • Accept all of the prompts that appear (e.g. Do you want to delete these certificates, etc.)
  • (Optional) Click the Fiddler.DefaultCertificateProvider link and verify that the dropdown is set to CertEnroll.
  • Exit and restart Fiddler.
  • Click Tools > Options.
  • Click the HTTPS tab.
  • Re-check the Decrypt HTTPS traffic checkbox.
  • Accept all of the prompts that appear (e.g. Do you want to trust this root certificate)

I think this is probably just one of many potential solutions for this, but it's coming up as one of the top search results for "your connection is not private fiddler" so I'll add it. Hopefully it'll help anyone else who comes across it.

NOTE: A few people have commented that they needed to restart Fiddler after running the above.

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  • @Chris - Hi Chris ! I can't make this work in my current setup. Can you please help me here - stackoverflow.com/questions/41902367/…
    – MasterJoe
    Commented Jan 31, 2017 at 18:27
  • This worked for me only after I uninstalled Fiddler and reinstalled it (I uninstalled while preserving existing settings). I have had Fiddler installed for quite a while, and have just used the automatic update feature as new versions have become available. There may be some issue with the mechanism for resetting certificates in this case as the fresh install allowed me to resolve the issue with the solution noted above.
    – cookch10msu
    Commented Apr 27, 2017 at 14:16
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    Did not work for me. However deleting the hostname from Chromes HSTS list did: stackoverflow.com/questions/33268264
    – Marc
    Commented May 3, 2017 at 6:42
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    I had to run the reset 2 times. The 2nd time I noticed more dialogs; specifically the 'Trust the Fiddler Root certificate' dialog didn't pop-up the first time.
    – spottedmahn
    Commented Aug 9, 2017 at 14:20
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    Switch to CertEnroll was seemingly not working until I restarted the Fiddler. Then reset the certificates and all works now. THX.
    – mivra
    Commented Aug 15, 2017 at 21:36
5

It's also worth checking whether a certificate generator plugin could be to blame.

In my case, Fiddler was using CertMaker.BCCertMaker. After uninstalling, reinstalling and reverting to CertEnroll engine, SSL works again.

  1. Uninstall Fiddler and all its settings.
  2. Install the latest version.
  3. In Confirm Tools -> Telerik Fiddler Options... -> HTTPS, confirm that CertEnroll engine performs certificate generation.
  4. On the same dialog, press Actions -> Reset All Certificates as in Chris's answer, accepting all prompts.
  5. Restart Fiddler.
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I was having the same issue with chrome / fiddler on ubuntu 20.04 not trusting the root certificate. I used the below steps to install fiddler - its a beta 'fiddler everywhere' which seems like its missing a few things that were there in windows version but it does work. Im not sure if this depends on (sudo apt install mono-complete). I tried the full version which did require mono so I definitely have that on my system but think mono is broken. Thinking that fiddler everywhere is somehow self contained.

I exported the certificate from fiddler options/https as crt (extensions for certs are confusing but I think this really is an x509 ssl certificate). To import to chrome I searched settings for 'manage certificates'. There are a bunch of tabs in that section and you have to select the authorities tab. I literally wasted an hour or more because I didn't see the tabs and was trying to import via the default 'your certificates' tab. Once I imported in the right place I was able to browse https traffic and fiddler everywhere could decrypt it.

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  • 1
    "There are a bunch of tabs in that section and you have to select the authorities tab" was a lifesaver. "I literally wasted an hour or more because I didn't see the tabs and was trying to import via the default 'your certificates' tab" - also happened to me. Thanks for posting this!
    – obe
    Commented Aug 13, 2020 at 15:38
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    This is a lifesaver answer. Literally a big thanks to you :)
    – essayoub
    Commented Aug 15, 2020 at 20:49
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Adding to the answer by @chris, make sure that you connected your device in my case, my phone, to fiddler after clearing the certificates. Otherwise, it will still have older certificates and will not get new ones.

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For "Fiddler Everywhere

  • download fiddler certificate from http://127.0.0.1:8866/ (when fiddler is running)
  • go to chrome settings, type "https" to quickly navigate to "Manage Certificates"
  • go to "Authorities" tab, click "Import" button
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