Which policy could have potentially prevented a successful brute force attack discovered by Abdul?

A password policy is crucial in protecting against brute force attacks, which involve systematically attempting a multitude of password combinations until the correct one is found. A robust password policy typically includes requirements for password complexity, length, expiration, and account lockout mechanisms after a specified number of failed login attempts. By enforcing complex and longer passwords, the difficulty of guessing them increases significantly, thereby enhancing security.

Additionally, an effective password policy may mandate regular password changes, reducing the chance of stolen credentials being used over extended periods and further thwarting brute force attempts. This policy could also include guidelines for the use of passphrases or multi-factor authentication to add an additional layer of security.

While other policies play essential roles in overall security posture, they do not directly address the vulnerabilities exploited in brute force attacks in the manner a password policy does. Access control policies relate more to permissions and user access levels, encryption focuses on securing data, and incident response policies deal with the procedures following a security incident. Thus, a robust password policy directly impacts the probability of successfully executing a brute force attack, making it the best choice in this scenario.