Elastic Security Detection Rules

Microsoft Build Engine Started an Unusual Process

Last updated 10 days ago on 2025-02-21
Created 5 years ago on 2020-03-25

About

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.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Defense EvasionTactic: ExecutionData Source: Elastic DefendData Source: SysmonData Source: Windows Security Event LogsLanguage: kuery
Severity
low
Risk Score
21
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

↳ Obfuscated Files or Information (T1027)(opens in a new tab or window)

↳ Trusted Developer Utilities Proxy Execution (T1127)(opens in a new tab or window)

False Positive Examples
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.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
New Terms Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process-*logs-system.security*logs-windows.forwarded*logs-windows.sysmon_operational-*winlogbeat-*
Related Integrations

endpoint(opens in a new tab or window)

windows(opens in a new tab or window)

system(opens in a new tab or window)

Query
host.os.type:windows and event.category:process and event.type:start and process.parent.name:("MSBuild.exe" or "msbuild.exe") and
process.name:("csc.exe" or "iexplore.exe" or "powershell.exe")

Install detection rules in Elastic Security

Detect Microsoft Build Engine Started an Unusual Process in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).