A security analyst must identify abnormal behavior on the server.

The analyst needs to establish baselines. Abnormal behavior can only be identified reliably when there is a known standard of normal activity. A baseline defines expected server behavior, such as CPU usage, memory consumption, network connections, logon patterns, running processes, service activity, traffic volume, and file access patterns. Once normal behavior is documented, deviations become easier to detect and investigate. Disabling unnecessary ports is system hardening, not behavior analysis. Patching the system reduces known vulnerabilities but does not define what is normal or abnormal. Alert tuning adjusts detection rules to reduce false positives or false negatives, but tuning is stronger after baselines are understood. Therefore, baseline establishment is the correct operational step for identifying abnormal server behavior.