A cybersecurity analyst is examining a complex dataset of threat intelligence information from various sources.

According to theCyberOps Technologies (CBRFIR) 300-215 study guidecurriculum, command-and-control (C2) communication is a strong indicator that a system has already been compromised and is actively under the control of an attacker. Sudden outbound traffic to high-risk regions and resolution of known malicious domains are high-confidence signs of an active threat. Therefore, prioritizing detection and disruption of this outbound traffic is critical to prevent further damage or data exfiltration.

While monitoring vulnerability exploitation (B) and gathering port scan data (D) are also valuable, they are more preventive or forensic in nature. The most immediate threat—and therefore the top priority—is stopping active C2 communications.