Suspicious Outlook Child Process

Last updated 9 days ago on 2025-05-05
Created 4 months ago on 2025-01-10

About

Identifies suspicious child processes spawned by MS Outlook, which can indicate a potential masquerading or the exploitation of a vulnerability on the application causing it to execute code.
Tags
Domain: EndpointOS: WindowsUse Case: Threat DetectionTactic: Defense EvasionTactic: PersistenceRule Type: BBRData Source: Elastic DefendLanguage: eql
Severity
low
Risk Score
21
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

Persistence (TA0003)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process-*
Related Integrations

endpoint(opens in a new tab or window)

Query
process where host.os.type == "windows" and event.type == "start" and
  process.parent.name : "outlook.exe" and
  not (
    (
      process.executable : (
        "?:\\Program Files\\*",
        "?:\\Program Files (x86)\\*",
        "?:\\Windows\\System32\\WerFault.exe",
        "?:\\Windows\\SysWOW64\\WerFault.exe",
        "?:\\Windows\\system32\\wermgr.exe",
        "?:\\Users\\*\\AppData\\Local\\Microsoft\\Teams\\current\\Teams.exe",
        "?:\\Users\\*\\AppData\\Local\\Temp\\NewOutlookInstall\\NewOutlookInstaller.exe",
        "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
        "?:\\Users\\*\\AppData\\Local\\Island\\Island\\Application\\Island.exe",
        "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
        "?:\\Users\\*\\AppData\\Roaming\\Zoom\\bin\\Zoom.exe",
        "?:\\Windows\\System32\\IME\\SHARED\\IMEWDBLD.EXE",
        "?:\\Windows\\System32\\spool\\drivers\\x64\\*",
        "?:\\Windows\\System32\\prevhost.exe",
        "?:\\Windows\\System32\\dwwin.exe",
        "?:\\Windows\\System32\\mspaint.exe",
        "?:\\Windows\\SysWOW64\\mspaint.exe",
        "?:\\Windows\\System32\\notepad.exe",
        "?:\\Windows\\SysWOW64\\notepad.exe",
        "?:\\Windows\\System32\\smartscreen.exe",
        "?:\\Windows\\explorer.exe",
        "?:\\Windows\\splwow64.exe"
      ) and process.code_signature.trusted == true  
    ) or
    (
      process.name : "rundll32.exe" and
      process.args : "*hpmsn???.dll,MonitorPrintJobStatus*"
    )
  )

Install detection rules in Elastic Security

Detect Suspicious Outlook Child Process in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).