Greetings, brave challengers! As you embark on the Padding Oracle Adventure, remember that the key to triumph lies in understanding the AES-128-CBC encryption's Achilles' heel—the vulnerable Cipher Block Chaining mode. May the flags be with you!

https://matrix.uctf.ir/

hint 1: login page grants access to a user with the credentials "guest" for both the username and password. hint 2: token structure: {"user": "<USERNAME>"}