Potential DLL Side-Loading via Microsoft Antimalware Service Executableedit

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.*

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



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

Version: 3

Rule authors:

  • Elastic
  • Dennis Perto

Rule license: Elastic License v2

Investigation guideedit

## Config

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 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule queryedit

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"))