Microsoft Build Engine Started by a System Process

An instance of the Microsoft Build Engine (MSBuild) was started by Explorer or the Windows Management Instrumentation (WMI) subsystem. This behavior is unusual and is sometimes used by malicious payloads.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 10

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where event.type in ("start", "process_started") and
  process.name : "MSBuild.exe" and
  process.parent.name : ("explorer.exe", "wmiprvse.exe")

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Trusted Developer Utilities Proxy Execution
- ID: T1127
- Reference URL: https://attack.mitre.org/techniques/T1127/
Sub-technique:
- Name: MSBuild
- ID: T1127.001
- Reference URL: https://attack.mitre.org/techniques/T1127/001/
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/

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