Program Files Directory Masquerading

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Identifies execution from a directory masquerading as the Windows Program Files directories. These paths are trusted and usually host trusted third party programs. An adversary may leverage masquerading, along with low privileges to bypass detections allowlisting those folders.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.process-*
  • logs-windows.*
  • endgame-*
  • logs-system.security*
  • logs-m365_defender.event-*

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:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Microsoft Defender for Endpoint

Version: 110

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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process where host.os.type == "windows" and event.type == "start" and
  process.executable : "C:\\*Program*Files*\\*.exe" and
  not process.executable : (
        "?:\\Program Files\\*.exe",
        "?:\\Program Files (x86)\\*.exe",
        "?:\\Users\\*.exe",
        "?:\\ProgramData\\*.exe",
        "?:\\Windows\\Downloaded Program Files\\*.exe",
        "?:\\Windows\\Temp\\.opera\\????????????\\CProgram?FilesOpera*\\*.exe",
        "?:\\Windows\\Temp\\.opera\\????????????\\CProgram?Files?(x86)Opera*\\*.exe"
  )

Framework: MITRE ATT&CKTM