Which method would BEST detect the presence of a rootkit in future incidents?

The best method to detect the presence of a rootkit in future incidents is through Endpoint Detection and Response (EDR). EDR tools are specifically designed to monitor endpoints for suspicious activity, including the subtle changes that rootkits may implement to hide themselves and maintain persistent access to systems. EDR solutions provide real-time monitoring and analysis of endpoint data, enabling security teams to identify malicious behaviors and rootkit signatures effectively.

Unlike full disk encryption, which primarily focuses on securing the data on a disk, EDR actively scans for indicators of compromise that could suggest rootkit activity. Network Intrusion Detection Systems (NIDS) are valuable for identifying network-based attacks but may not detect rootkits that operate at a system level without generating noticeable network traffic. Data Loss Prevention (DLP) is oriented towards protecting data from unauthorized access and exfiltration rather than specifically detecting hidden malware like rootkits. Therefore, EDR is the most effective tool among the options for the detection of rootkits.