Microsoft Build Engine Started an Unusual Process
An instance of MSBuild, the Microsoft Build Engine, started a PowerShell script or the Visual C# Command Line Compiler. This technique is sometimes used to deploy a malicious payload using the Build Engine.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source category
- event_index
Known benign triggers
- The Build Engine is commonly used by Windows developers but use by non-engineers is unusual. If a build system triggers this rule it can be exempted by process, user or host name.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| blog.talosintelligence.com/2020/02/building-bypass-with-msbuild.html | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 9d110cb3-5f4b-4c9a-b9f5-53f0a1707ae6
- Tagged by the source as
- Data Source: Elastic DefendData Source: SysmonData Source: Windows Security Event LogsDomain: EndpointNoise: LowOS: WindowsPerformance: NormalPlatform: WindowsResources: Investigation GuideRule Type: New TermsTactic: Defense EvasionTactic: ExecutionUse Case: Threat Detection
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3