Microsoft Build Engine Started by a Script Process

An instance of MSBuild, the Microsoft Build Engine, was started by a script or the Windows command interpreter. This behavior is unusual and is sometimes used by malicious payloads.

Rule type: new_terms

Rule indices:

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

Severity: low

Risk score: 21

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:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Defense Evasion
Tactic: Execution
Data Source: Elastic Defend

Version: 311

Rule authors:

Elastic

Rule license: Elastic License v2

Setup

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Setup

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 version 8.2. Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate event.ingested to @timestamp. For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html

Rule query

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host.os.type:windows and event.category:process and event.type:start and (
  process.name.caseless:"msbuild.exe" or process.pe.original_file_name:"MSBuild.exe") and
  process.parent.name:("cmd.exe" or "powershell.exe" or "pwsh.exe" or "powershell_ise.exe" or "cscript.exe" or
    "wscript.exe" or "mshta.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/
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
Sub-technique:
- Name: PowerShell
- ID: T1059.001
- Reference URL: https://attack.mitre.org/techniques/T1059/001/
Sub-technique:
- Name: Windows Command Shell
- ID: T1059.003
- Reference URL: https://attack.mitre.org/techniques/T1059/003/
Sub-technique:
- Name: Visual Basic
- ID: T1059.005
- Reference URL: https://attack.mitre.org/techniques/T1059/005/

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