Microsoft Build Engine Started by an Office Application

An instance of MSBuild, the Microsoft Build Engine, was started by Excel or Word. This is unusual behavior for the Build Engine and could have been caused by an Excel or Word document executing a malicious script payload.

Rule type: eql

Rule indices:

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

Severity: high

Risk score: 73

Runs every: 5m

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

Maximum alerts per execution: 100

References:

https://blog.talosintelligence.com/2020/02/building-bypass-with-msbuild.html

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 9

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

process where event.type in ("start", "process_started") and
  process.name : "MSBuild.exe" and
  process.parent.name : ("eqnedt32.exe",
                         "excel.exe",
                         "fltldr.exe",
                         "msaccess.exe",
                         "mspub.exe",
                         "outlook.exe",
                         "powerpnt.exe",
                         "winword.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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