This is the test cases used in A Multifaceted Study on the Use of TLS and Auto-detect in Email Ecosystems. Read the paper for more details.

To accommodate different syntax, you will see there are three folders with the respective protocols.

• T1: STARTTLS stripping
• T2: Replace incoming ServerHello in TLS negotiation
• T3: Reject STARTTLS command
• T4: Disrupt a complete TLS handshake

1. Setup the mitmproxy according to their official website.

2. Modify the mitmproxy with the below command

git clone https://github.com/tls-downgrade/email-security.git
cp -r  imap/ pop3/ smtp/ ./mitmproxy
cp next_layer.py ./mitmproxy/addons/

3. Run the mitmproxy with the following command:

mitmproxy --set spoof-source-address --ssl-insecure --mode transparent --showhost -s <folder/file.py>