Downgrade the protocol

Question

Downgrade the protocol

mpgn opened this issue 6 years ago · 6 comments

For now and after many attempt, I didn't find a proper way to downgrade the protocol to SSLv3 if TLS was negotiate first. (with old version of openssl/browser) that didn't support TLS Fallback SCSV.

Sending a Handshake failure during the handshake was not working for example with firefox. I also didn't find a real example internet.

Answer 1 · 2018-04-22T16:48:54.000Z

Okay, I finally found a way ! but in chrome, not firefox 😆

This is the capture of the wireshark traffic, the proof :

downgrade.zip

I will implement the downgrade method during the next week and push the code after ! 😄

Answer 2 · 2018-04-25T13:20:08.000Z

It will be very helpful. Please let me know when it's available.

Answer 3 · 2018-04-29T15:52:59.000Z

Any updates related to pushing the code will be very helpful 👍

Answer 4 · 2018-05-02T10:04:15.000Z

mpgn commented 6 years ago

🎉1

Answer 5 · 2018-05-02T15:38:38.000Z

can't wait to test it 👍

Answer 6 · 2018-05-02T16:03:28.000Z

How it works ?

during the handshake (after the hello client), the exploit send a handshake_failure 15030000020228 then the browser should resend a hello client with SSLv3.0 as default protocol. Tested on chrome version 15 but it's not working on Firefox (I think he doesn't support protocol renegotiation)