Which of the following practices can render an organization's server machine vulnerable to malware incidents?

Enabling all available services on a server can create a significant security risk. Each service that is enabled potentially has its own vulnerabilities, which could be exploited by attackers. Many services might offer unnecessary functionalities that aren't actively used by the organization, increasing the attack surface. This means that the more services running, the higher the chance one might be misconfigured or have known weaknesses that can be attacked by malware or hackers.

In contrast, practices such as using strong passwords, implementing firewalls, and restricting access to certain users are fundamentally designed to enhance security. Strong passwords help protect against unauthorized access; firewalls help in filtering out malicious traffic before it can reach the server; and restricting access ensures that only authorized personnel can interact with the server's sensitive components, reducing the risk of internal threats as well.