web ctf hints
spoiler-free hints for web exploitation challenges.
SQL injection · XSS · LFI · SSRF · IDOR · SSTI · prototype pollution · command injection
what web ctf challenges look like
web CTF challenges give you a URL, source code, or both. the goal is usually to read a flag file, gain admin access, or exploit a server-side vulnerability. common categories include SQL injection, cross-site scripting (XSS), server-side template injection (SSTI), local file inclusion (LFI), SSRF, insecure direct object references (IDOR), and command injection.
common web challenge types
- SQL injectionclassic error-based, blind boolean, time-based — look for input fields that touch a database. test with a single quote.
- XSSreflected, stored, DOM-based — look for unsanitized user input rendered back in the page. try <script>alert(1)</script>.
- LFI / RFIfile inclusion via path traversal — look for file parameters like ?page= or ?include=. try ../../../etc/passwd.
- SSRFserver-side request forgery — look for URL parameters the server fetches. target internal services like http://localhost/.
- SSTItemplate injection — test with {{7*7}} or ${7*7} or <%= 7*7 %> in input fields depending on the framework.
- IDORinsecure direct object reference — look for predictable IDs in URLs or API calls. try changing /api/user/1 to /api/user/2.
- command injectionlook for inputs that pass user data to shell commands. test with ; id or | whoami.
- prototype pollutionlook for object merge or clone operations in JavaScript. test with __proto__[admin]=true in JSON bodies.
how hints work for web challenges
describe your challenge — the URL, what the app does, what you've already tried. CTF Helper gives you a nudge first (what class of vulnerability to look for), then a technique hint (specific approach or tool), then a near-solution hint (exact steps without the flag). you choose when to go deeper.
faq
how do I identify which web vulnerability a challenge has?+
match the symptom to the class. input reflected back in the page points to XSS; a single quote that breaks the response or changes behaviour points to SQL injection; a file or path in a URL parameter points to LFI; a URL the server fetches on your behalf points to SSRF. if source code is provided, read it first — the intended bug is usually visible.
do I need Burp Suite to solve web CTF challenges?+
not always. curl and the browser dev tools handle most challenges. Burp helps when you need to intercept, replay, and fuzz requests quickly — especially for blind injection, auth bypass, or anything requiring hundreds of variations. the free Community edition is enough for CTFs.
how do the hints avoid spoiling the flag?+
hints escalate across three tiers — first the vulnerability class to look for, then the technique or tool, then the specific steps — but never the final payload containing the flag. you choose how far down the ladder to go.