Hacking Crypto Part IV: Web and mobile applications

The final installment of the Hacking Cryptography series delves into cryptographic vulnerabilities in web and mobile applications, emphasizing their significance for bug bounty hunters. Cryptographic security is crucial for protecting sensitive data such as credit card numbers and user credentials in online transactions. The series highlights several common vulnerabilities, including JSON Web Token (JWT) issues, predictable token and key generation, hardcoded keys, padding oracle vulnerabilities, and improper use of initialization vectors (IVs). JWT vulnerabilities are particularly impactful, as they can lead to user impersonation and privilege escalation if signature validation is flawed. Predictable token generation and hardcoded keys can compromise session security and data integrity, while padding oracle vulnerabilities allow attackers to decrypt data without the key. The series underscores the importance of cryptographically secure pseudo-random number generators and proper key management. It also explores real-world examples of these vulnerabilities, demonstrating their potential risks and exploitation techniques, thus encouraging bug bounty hunters to focus on practical deployment issues in cryptographic systems.