Which Windows event categories are most important for incident investigation?

• A. Security event logs for authentication behavior; System logs for service/restarter events; Application logs for application errors and crashes; Sysmon events if installed.
• B. Only Security event logs matter.
• C. Only System logs matter.
• D. Only Application logs matter.

Answer: (A)

Windows incident investigation relies on data from multiple event logs, not just a single source. Security event logs capture authentication activity, logons, privilege use, and account changes, which helps detect suspicious sign-ins and credential misuse. System logs reveal service and driver status, startup/shutdown events, and restarts, which can indicate tampering, failures, or maintenance actions. Application logs show software errors and crashes that may signal malware or misbehavior at the application level. If Sysmon is installed, its detailed process creation, network activity, file and registry changes, and other events dramatically improve visibility and enable precise correlation across activities. Together, these sources give a fuller, more actionable picture of an incident than any one log type alone. Relying on only one category risks missing important indicators: for example, focusing solely on security logs can miss service-related changes and application failures; system logs alone miss authentication and application behavior; application logs alone miss sign-ins and system activity.