Hi! Here I briefly describe my experience on setting up Fiddler on Kali Linux and capturing traffic from Firefox ESR browser.
Installing Fiddler
- Install mono
sudo apt install mono-complete
- Download Fiddler for linux from www.telerik.com/docs/default-source/fiddler/fiddler-linux.zip?sfvrsn=2 and unzip the package.
- Run Fiddler.exe with mono
mono Fiddler.exe
Configuring Firefox to capture traffic
- Open the Firefox browser and press ‘Alt’ button. The tool bar at the top will appear.
- Next, Goto Edit –> Preferences to view the “Options” in Firefox.
- Select Advanced –> Network .
- Click on “Settings”. It says “No Proxy”
- Tick the “User system proxy settings” option and press OK.
Configuring Firefox to trust Fiddler root certificate
If you try to load a https page at Firefox you will see following error. To avoid that need to configure Firefox with Fiddler’s root certificate.
Step 1: Download the Fiddler’s root certificate.
- At Fiddler, goto Tools –>Options .
- Select “HTTPS” tab.
- Press “Actions” button at the right top corner.
- Select “Export Root Certificate to Desktop”.
Step 2: Import the Fiddler’s root certificate at Firefox browser.
- Goto Edit –> Preferences –> Advanced –> Certificate.
- Press “View Certificate” button.
- Select “Import” –> Choose the root certificate on desktop.
- Tick “Trust this CA to identify websites”. Press OK. done.
Cheers!