CTF web challenges

When it applies

The handout is a URL (sometimes plus source). The goal is almost always to read a flag file (/flag, /flag.txt, an env var, or a DB row) — so every bug you find should be steered toward read a file, run a command, or become admin. This skill is the CTF routing layer; work the deep techniques with web-ssti, web-ssrf, web-sqli, web-lfi-path-traversal, web-auth-jwt, web-deserialization, web-command-injection, web-file-upload.

Why it works

CTF web challenges strip an app to one intended bug plus decorations, so the surface is small and the bug is findable by enumeration, not luck. Provided source turns black-box guessing into reading comprehension; the framework banner (Flask/PHP/Express) predicts the bug class before you send a request.