Wireshark Use Certificate to Decrypt TLS Stream

In the previous part of this blog post, we explored how to decrypt TLS streams using the web server's private key. However, there are cases where you may not have access to the private key or want to use a different method for decryption. This is where Wireshark comes in handy. In this article, we will learn how to use certificate to decrypt TLS streams with Wireshark.

When you set up your curl command with the SSLKEYLOGFILE environment variable, it writes down the secret keys that are exchanged during the TLS handshake. You can then use these secrets in Wireshark to decrypt the TLS stream. To do this, you need to set up your curl command as follows:

`curl.exe –verbose –insecure –tls-max 1.2 –ciphers AES256-SHA –dump-header 01.headers –output 01.data –trace 01.trace –trace-time`

In this command, we are using the `–verbose` option to get more information about the TLS handshake, `–insecure` option to disable certificate verification, and `–tls-max 1.2` and `–ciphers AES256-SHA` options to force a cipher suite that is based on RSA for the exchange of the pre-master secret.

Once you run this command, you will get a file called `secrets-1.txt` that contains the secret keys exchanged during the TLS handshake. You can then use Wireshark to decrypt the TLS stream by going to the preferences for the TLS protocol and setting the “(Pre)-Master-Secret log filename” to `secrets-1.txt`.

When you do this, you will see that the TLS data is decrypted, as evidenced by the appearance of green HTTP protocol packets in Wireshark. This means that you have successfully used a certificate to decrypt the TLS stream.

In conclusion, using Wireshark with a certificate is a powerful way to decrypt TLS streams without having access to the private key. By setting up your curl command and configuring Wireshark correctly, you can capture and analyze encrypted TLS traffic in real-time.

Wireshark use certificate to decrypt