Unable to Capture request in My Mac Using Fiddler Everywhere

[Varadharajan]

Hi -- I tried installing Fiddler Everywhere for my MBP and i enabled Capture HTTPS Traffic and trusted the root Certificate also. I am still not able to capture the traffic in Fiddler.

[Nick Iliev]

Hi Varadharajan,

 

Are you by chance using VPN software or network security tools? If so, you could try to disable them and then try Fiddler Everywhere. If that is not the issue you could send us more details about your environment (specific OS version) and also screenshots of your proxy configuration before and after you start Fiddler.

 

Regards,
Nick Iliev
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[Murad]

The same for me. I was working fine right after I installed it. But something happened recently I can no longer capture any traffic HTTPS and HTTP. Maybe it has something to do with MacOS updates.

[Nick Iliev]

Hello Murad Khafizov,

 

If possible please provide the details I've requested in my previous answer:

Are you by chance using VPN software or network security tools (VPN like CiscoVPN is disabling the HTTPS capturing)? If so, you could try to disable them and then try Fiddler Everywhere. If that is not the issue you could send us more details about your environment (specific OS version) and also screenshots of your proxy configuration before and after you start Fiddler.

 

Regards,
Nick Iliev
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[Murad]

Hi Nick,

I think I found the reason. After I started the Fiddler Everywhere as admin (sudo + path in Terminal) is started capturing. But if I start it the app normally, it doesn't capture.

 

And what also came to my mind, is that before the app was asking for admin login/password every time, when I was enabling/disabling capturing. But now it's not the case. It means it starts with no admin privileges and doesn't ask for them.

 

Hope it's helpful

 

Best regards,

Murad

[Murad]

And in addition:

- MacOS Catalina 10.15.5 

- No VPN software

 

If I start capturing in Fiddler that started without admin privileges, proxy settings don't change.

If I start capturing in Fiddler that started with admin privileges, proxy setting change to 127.0.0.1:8866 and it all works.

[Nick Iliev]

Hi Murad,

 

Thanks for the provided input - Indeed on MacOS and Linux, an account with administrative rights Is needed in order to be able to capture secure traffic (noted here).

 

Regards,
Nick Iliev
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[Murad]

Hi Nick

Thanks, I didn't know that. But can Fiddler at least ask for administrative privileges itself, when the user enables capturing?

I think that exactly how it behaved before. And now it's just silent.

[Nick Iliev]

Hello Murad,

 

On Mac OS to be able to trust the root certificate you will be prompted to enter your admin username and password. We are currently updating the documentation for the Linux workflow.

 

Regards,
Nick Iliev
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[Murad]

What I'm asking for is different. It doesn't matter if I want to capture SSL-traffic or not. It's relevant even for plain traffic.

Basically the original issue is that Fiddler Everywhere has to be started with sudo on Mac in order to capture. Right?
It's not really convenient. If a user doesn't start it with sudo, then capturing doesn't work and there is no notification about it.

The solution here could be, that Fiddler prompts to enter admin password every time, when user enables or disables capturing in already running Fiddler instance. Is it possible?

 

 

As far as I remember that's how it it behaved at some point, but it's the behavior got broken at some point.

 

Thanks

[Nick Iliev]

Hi Murad,

 

Thanks for the detailed explanation. Fiddler Everywhere should not ask for a super user account (sudo) to capture non-secure traffic (to set the proxy) - this is how it is working on Catalina 10.15.4 and previous versions. I've escalated the issue to our QAs and we are currently testing different scenarios against the latest MacOS version. We will post here once we have more information related to the case.

 

Regards,
Nick Iliev
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