サイバーセキュリティ企業のフォレンジックアナリストとして、あなたはクライアントのオフィスで発生した情報漏洩事件の調査を任されました。この漏洩は複数のサーバーに影響を及ぼしており、各サーバーにはそれぞれ独自のログとイベントが記録されています。分析を効率化し、漏洩の根本原因を特定するために、どのようなイベント相関分析手法を用いるべきでしょうか?
正解:A
Option A. Time-based correlation is the best answer because the scenario involves multiple servers , each generating separate logs and events, and the investigator needs to reconstruct the breach efficiently and identify its root cause . CHFI v11 explicitly includes Types of Event Correlation , Event Correlation Approaches , Timeline and Kill Chain Analysis , and centralized logging using SIEM solutions as part of evidence examination and network/log analysis.
When several systems are involved, the most effective first way to connect the activity is to correlate events by time so the examiner can determine the sequence of actions across hosts. This helps answer critical questions such as what happened first, which server was initially affected, how the attacker moved, and when key indicators appeared. That is exactly how investigators build a timeline and isolate the origin or progression of an incident.
Log-based correlation groups similar logs, alert-based correlation focuses on alerts, and rule-based correlation applies predefined logic, but the question stresses identifying the root cause across multiple servers and logs , which is most directly supported by constructing a chronological event sequence .
Therefore, under CHFI event-correlation and timeline-analysis objectives, time-based correlation is the strongest answer.