ReliaQuest Security Analyst / Greymatter Specialist Practice Test

SIEMs detect threats by correlating events from multiple data sources to build a complete view of what’s happening across the environment. In practice, this means ingesting logs from endpoints (the operating system), the network (traffic and security devices), and applications (web apps, databases, middleware). OS logs reveal who logged in, when, and what actions were taken; network logs show connections, flows, and unusual traffic patterns; application logs expose user actions, API calls, and errors that could signal abuse. With all three sources, the SIEM can spot complex attack patterns like credential abuse, lateral movement, or data exfiltration that wouldn’t be visible from a single source alone. Printer usage logs are not typically used for threat detection because they usually offer limited security-relevant information and add noise relative to the value gained. So the most effective and common ingestion set includes OS logs, network logs, and application logs.