Which of the following ensures no default passwords remain in systems?

Changing passwords is vital to ensuring that no default passwords remain in systems because default passwords are often well-known and documented, making them a significant security risk. When systems are installed or set up, they frequently come with preset passwords that are intended for initial access. If these passwords remain unchanged, they create vulnerabilities that attackers can exploit.

By implementing a policy of changing passwords, organizations can replace default credentials with strong, unique passwords that meet security best practices. This reduces the likelihood of unauthorized access and helps maintain the integrity and confidentiality of the system.

Regular auditing, system patching, and data cleanup contribute to overall security posture but do not specifically address the issue of default passwords directly. Auditing can identify weak passwords but does not enforce their change, patching maintains the system's security against vulnerabilities, and data cleanup focuses on removing unwanted data rather than credential management. Therefore, actively changing passwords is the most effective approach to mitigate risks associated with default passwords.