What prerequisites are needed to perform a Padding Oracle Attack on Microsoft Exchange using CVE-2021-31196?

To perform the attack, you need two things: First, obtain the ciphertext and its corresponding IV (Initialization Vector). In Exchange cookies, the `cadata` value is the ciphertext and `cadataIV` is the IV. Second, you must be able to trigger the decryption process and interpret the result. This is done by sending a GET request to `/owa/` with the cookie set, and checking the `reason` parameter in the 302 redirect response—`reason=2` indicates successful decryption. For more background, see the initial ProxyOracle Exploitation Analysis 1—CVE-2021-31195 article.