Your IT security team is responding to a denial of service attack against your server. They have taken measures to block offending IP addresses. Which type of threat control is this?

Detective controls identify and log security events as they occur but do not take active steps to stop or reverse the ongoing attack.

Preventive controls are implemented before an attack to stop it from happening; since the DoS attack is already underway, blocking IPs at this stage is reactive, not preventive.

Responsive is not a recognized category in standard security control frameworks such as NIST SP 800-53; the correct term for actions taken during or after an active incident is corrective.

Corrective controls are security measures applied during or after a security incident to limit harm and restore normal operations. Blocking specific attacker IP addresses while a DoS attack is actively occurring is corrective - it addresses a threat that is already causing damage and works to restore the affected service to normal function.