Math Solver
Automate solving 100 consecutive linear equations within a single HTTP session to unlock the flag.
Session
A Too Small Reminder — Session ID Enumeration
Register, log in, notice the session_id cookie is a small integer. Brute-force integers upward from 30 until the admin session is hit and the flag appears.
Truly Random Signature — Predictable Session Token Analysis
The server issues session tokens that are predictable or reusable. Requesting the site twice, comparing the Set-Cookie headers, and identifying the pattern allows forging or reusing an admin-level token.