Which of the following is a countermeasure against malware?

System hardening by disabling unnecessary services is an effective countermeasure against malware because it minimizes the number of entry points that an attacker can exploit. By limiting the services that are running on a system, you reduce the attack surface available to malicious software. Many malware programs target specific services or applications, so by disabling those that are not needed for the system's functionality, you significantly decrease the chances of infection.

Additionally, unnecessary services can sometimes have vulnerabilities that, if left enabled, could be exploited by malware. When these services are disabled, it not only helps to protect the system from potential exploit but also simplifies the management of security, as fewer components need to be monitored and kept up to date.

Other options, such as running applications with admin rights, ignoring software updates, and using default firewall settings, do not enhance security and may even open up vulnerabilities that malware can exploit.