JWT labs prerequisite?

Basic HTTP headers and base64. Complete auth labs first if available.

Labs & Learning PathsEnglish

JWT Security Lab Guide

JWT security labs teach token structure (header.payload.signature), weak HMAC secrets, algorithm confusion (RS256 to HS256), and claim tampering. Cyfotok JWT labs provide vulnerable APIs that accept manipulated tokens.

Published 1 June 2025Updated 1 June 2026

JWT basics for labs

Three base64 parts. Signature validates integrity. If secret is 'secret123', hashcat cracks it. If server accepts alg:none or HS256 with public key as secret — game over.

Common lab scenarios

Change role claim from user to admin. Swap algorithm. Brute-force weak signing key. Kid header injection.

Tools

jwt.io for decoding, hashcat/john for cracking, Burp JWT Editor extension.

Frequently asked questions

JWT labs prerequisite?: Basic HTTP headers and base64. Complete auth labs first if available.

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