What action do some viruses attempt to take against virus scanners to evade detection?

Viruses often attempt to evade detection by pausing or disabling virus scanners, which is a strategic approach to ensure they can operate undetected on an infected system. When a virus successfully disrupts the functioning of a virus scanner, it minimizes the likelihood of being detected during routine system checks. By temporarily pausing or deactivating the protective measures that scanners provide, the virus can carry out its malicious activities without interference.

This action is particularly dangerous because it not only allows the virus to propagate but also creates a false sense of security for the user, who may believe their system remains protected. In contrast, other options, such as modifying scanning signatures or alerting users of their presence, do not directly enhance the virus's operational effectiveness in the same way. Additionally, reducing system resource usage does not contribute to evading detection and may not be a primary concern for the virus itself. Instead, the focus remains on avoiding detection to cause maximum damage or data theft.