Changing default credentials is an essential security measure to prevent unauthorized access, as many attack vectors involve using known defaults to gain control over systems. Attackers often rely on databases of default usernames and passwords to easily compromise devices that have not had their credentials changed from the defaults set by the manufacturer. Regularly updating system passwords to complex, unique passwords helps to improve security. Conducting a vulnerability scan or updating firmware, while both important, would not be as immediate and direct a mitigation for default credentials as changing them. Disabling remote management could be part of a broader hardening process, but it does not directly address the risk of default credentials being exploited.