What are JWT vulnerabilities and how can I mitigate them?

What are JWT vulnerabilities and how can I mitigate them?

JWT (JSON Web Token) vulnerabilities can include issues like token theft, replay attacks, and improper validation. To mitigate these, you should use strong signing algorithms, implement token expiration, and validate tokens properly on the server.

Can you explain how token theft occurs?

Token theft can occur through various means, such as XSS attacks, where an attacker injects malicious scripts to steal tokens from a user's browser. It's crucial to sanitize inputs and use secure storage for tokens.

What are replay attacks and how can I prevent them?

Replay attacks happen when an attacker captures a valid JWT and reuses it to gain unauthorized access. To prevent this, you can implement nonce values or use short-lived tokens that expire quickly.

Are there any best practices for storing JWTs securely?

Yes, store JWTs in secure, HttpOnly cookies to prevent access via JavaScript. Avoid local storage for sensitive tokens.