The Hacker101 Encrypted Pastebin challenge is a classic web security exercise focused on breaking a Padding Oracle Attack. In this scenario, you are presented with a web application that stores "pastes" and encrypts them using AES in CBC mode. The Objective
You find default credentials for a staging server (admin:admin123). You need to send this to the security team. If you send it in plain text over email, it is intercepted. You paste it into an encrypted paste, burn after reading, and DM the link to the triager. hacker101 encrypted pastebin
CBC is Fragile: Without a Message Authentication Code (MAC), CBC is vulnerable to bit-flipping and padding oracles. The Hacker101 Encrypted Pastebin challenge is a classic
Flag 2: Often involves using the oracle to encrypt a custom string (Bit-Flipping or further Oracle manipulation) to gain unauthorized access to a protected page or administrative function. Summary of Flags Description Flag 0 Initial Access Exploit the Padding Oracle to decrypt a standard post. Flag 1 Admin/Hidden Data You need to send this to the security team
By observing these differences, you can use the server as an "oracle" to decrypt the data byte-by-byte without knowing the secret key. 2. The Attack Mechanism (Padding Oracle)
The challenge gifts you the ability to modify the URL parameters: ?id=...&iv=...&data=...