Potential DLL Side-Loading via Microsoft Antimalware Service Executable

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Potential DLL Side-Loading via Microsoft Antimalware Service Executable

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Identifies a Windows trusted program that is known to be vulnerable to DLL Search Order Hijacking starting after being renamed or from a non-standard path. This is uncommon behavior and may indicate an attempt to evade defenses via side-loading a malicious DLL within the memory space of one of those processes.

Rule type: eql

Rule indices:

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

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:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Defense Evasion
  • Elastic Endgame

Version: 101

Rule authors:

  • Elastic
  • Dennis Perto

Rule license: Elastic License v2

Investigation guide

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Rule query

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process where event.type == "start" and
  (process.pe.original_file_name == "MsMpEng.exe" and not process.name : "MsMpEng.exe") or
  (process.name : "MsMpEng.exe" and not
        process.executable : ("?:\\ProgramData\\Microsoft\\Windows Defender\\*.exe",
                              "?:\\Program Files\\Windows Defender\\*.exe",
                              "?:\\Program Files (x86)\\Windows Defender\\*.exe",
                              "?:\\Program Files\\Microsoft Security Client\\*.exe",
                              "?:\\Program Files (x86)\\Microsoft Security Client\\*.exe"))

Framework: MITRE ATT&CKTM