SSL Decryption/Spoofing

The app is able to decrypt SSL and spoof the remote site certificate. It acts as a MITM (sitting between client and remote server) decrypting HTTPS communication on-the-fly without a client spotting any difference.

Disclaimer

This app was build solely for educational purposes. I did that to learn how the SSL encryption can be done. Author doesn't take any responsibility for misuse of this project.

Prerequisites

• Client must have the self-signed CA cert installed in Chrome/system
• Client must have set the transparent (system/browser) proxy pointing at this app

Details

• See conf/configuration.go for configuration options
• In default the transparent proxy runs on 0.0.0.0:8080
• In default the internal web server for SSL spoofing runs on 0.0.0.0:8443

Setup

Generate certification authority (https://deliciousbrains.com/ssl-certificate-authority-for-local-https-development/)

1. openssl genrsa -des3 -out myCA.key 2048
2. openssl req -x509 -new -nodes -key myCA.key -sha256 -days 1825 -out myCA.pem
3. Configure the app to use these generated key and cert
4. Run the app
5. Import the myCA.pem into Chrome under Trusted Root Certification Authorities (windows) or into the key-chain (Mac) - More details can be found here
6. Setup the HTTPS proxy (e.g. using SwitchyOmega)
7. Test going to an HTTPS site and check the certificate details. They should resemble what is in crypto/spoof.go#spoofCertificate

How do I find if it's working?

• HTTPS pages render fine in the chrome browser (no security warning)
• After clicking the small lock icon next to the domain in the address bar and selecting Certificate option you should see the spoofed cert
• Logs of the app should show connections going through

Sources used during the implementation

• https://deliciousbrains.com/ssl-certificate-authority-for-local-https-development/
• https://shaneutt.com/blog/golang-ca-and-signed-cert-go/