const isLocalhost = (url) => host === '127.0.0.1' ; if (isLocalhost(url)) return res.status(400).send('Localhost requests blocked');
http://[::1]:3000/encryptionkey.txt
curl "http://localhost:3000/api/Image?url=http://localhost:3000/encryptionkey.txt" HTTP 200 with the encryption key in the body (may be text/plain despite image content-type header). 5. Impact Assessment | Attack Vector | Impact | |---------------|--------| | Localhost file read | Exposure of source code, config files, secrets | | Internal port scan | Discovery of admin panels, databases, Redis, Jenkins | | Cloud metadata theft | IAM credentials, access tokens → cloud account compromise | | Service interaction (e.g., Redis, Memcached) | Potential RCE via protocol smuggling | owasp juice shop ssrf
The challenge is solved when the student successfully extracts encryptionkey.txt . The OWASP Juice Shop SSRF challenge provides a realistic, hands-on example of how an innocent-looking image fetch endpoint can become a gateway to internal resources. By exploiting it, attackers can read local files, scan internal networks, and steal cloud credentials. Mitigation requires strict allowlisting, network controls, and never trusting user-supplied URLs. const isLocalhost = (url) => host === '127