Isolating the endpoint device is the best course of action to prevent further damage, as it will prevent the potential spread of malware or compromise to other devices or systems on the network. Wiping and resetting the endpoint device may be a possible recovery option, but it is not the first priority and it may also destroy valuable forensic evidence. Powering off the endpoint device may also cause loss of data or evidence, and it may not stop the attack if the device is remotely controlled. Running a virus scan on the endpoint device may not be effective if the device is already compromised, and it may also trigger malicious actions by the attacker. References = CISM Review Manual 15th Edition, page 203. Boosting Cyberresilience for Critical Enterprise IT Systems With COBIT and NIST Cybersecurity Frameworks1, Endpoint Security: On the Frontline of Cyber Risk2.
The best course of action to prevent further damage is to isolate the endpoint device. Isolating the endpoint device will prevent the compromised system from connecting to other systems on the network and spreading the infection. Other possible courses of action include wiping and resetting the endpoint device, running a virus scan, and powering off the endpoint device. However, these actions will not prevent the compromised system from continuing to spread the infection.