LoFP LoFP / microsoft antimalware service executable installed on non default installation path.

Techniques

Sample rules

Potential DLL Side-Loading via Microsoft Antimalware Service Executable

Description

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.

Detection logic

process where host.os.type == "windows" and 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",

            /* Crowdstrike specific exclusion as it uses NT Object paths */
            "\\Device\\HarddiskVolume*\\ProgramData\\Microsoft\\Windows Defender\\*.exe",
            "\\Device\\HarddiskVolume*\\Program Files\\Windows Defender\\*.exe",
            "\\Device\\HarddiskVolume*\\Program Files (x86)\\Windows Defender\\*.exe",
            "\\Device\\HarddiskVolume*\\Program Files\\Microsoft Security Client\\*.exe",
            "\\Device\\HarddiskVolume*\\Program Files (x86)\\Microsoft Security Client\\*.exe"
    )
  )
)