Microsoft Build Engine Started by a Script Process

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Microsoft Build Engine Started by a Script Process

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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: 209

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&CKTM