MSBuild.exe is Microsoft’s build engine for compiling, packaging, and automating Windows software projects. It reads project files and runs build tasks, which makes it a normal and trusted part of many developer and administrator workflows. Because it is signed by Microsoft and commonly present on Windows systems, security tools may treat it as low risk.
Attackers abuse that trust by using MSBuild.exe as a launcher for malicious code, scripts, or embedded payloads. This can help bypass allowlists and make execution look like routine development activity. In defenses, suspicious MSBuild use is often a signal to inspect parent processes, command-line arguments, loaded modules, and child processes. Unusual execution from user profile folders, email attachments, or non-development hosts is especially important. Restricting where MSBuild can run, logging process creation, and correlating it with file and network activity can help reveal abuse even when the executable itself is legitimate.