A restaurant distribution center recently suffered a password spray attack targeting the Cisco Secure Firepower Threat Defense VPN headend. The attack attempts to gain unauthorized access by trying common passwords across many accounts. The attack poses a significant security threat to the organization’s remote access infrastructure. To enhance the security of VPN setup and minimize the risk of similar attacks in the future, the IT security team must implement effective mitigation measures. Which technique effectively reduces the risk of this type of attack?