Detection Engineering: A Case Study

This article explains the role and lifecycle of detection engineering and demonstrates those concepts with a practical case study: building a KQL detection for remote DCOM execution using Microsoft Defender XDR. It covers research, hypothesis formation, query development (joining network and process telemetry to identify svchost.exe instances running with "-k DcomLaunch" and their spawned child processes), testing and false-positive reduction (excluding WerFault.exe), deployment best practices (version control and CI/CD), and the need for continual revision to address gaps such as DLL and script injection vectors.