webPromedium

Criticalops

hackthebox

Task: Next.js infra-monitoring app whose JWT is signed in the browser with a hardcoded HMAC secret shipped in the client bundle. Solution: recover the secret 'SecretKey-CriticalOps-2025' from the login page chunk, forge an HS256 admin token, and read the flag from an admin-visible ticket via GET /api/tickets.

nextjs jwt hardcoded_secret broken_access_control client_side_auth privilege_escalation jose

jwt_forgeryclient_bundle_analysishmac_secret_recoveryrole_claim_tamperingbroken_access_control_exploitation

$ ls tags/ techniques/

nextjs jwt hardcoded_secret broken_access_control client_side_auth privilege_escalation jose

jwt_forgeryclient_bundle_analysishmac_secret_recoveryrole_claim_tamperingbroken_access_control_exploitation

Analysis

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$ python3 exploit.py --target 192.168.1.1 --port 8080
[*] Connecting to target...
[+] Shell obtained!

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