Suspicious macOS MS Office Child Process

Last updated 8 months ago on 2025-02-04
Created 5 years ago on 2021-01-04

About

Identifies suspicious child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, and Excel). These child processes are often launched during exploitation of Office applications or by documents with malicious macros.
Tags
Domain: EndpointOS: macOSUse Case: Threat DetectionTactic: Initial AccessData Source: Elastic DefendLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Initial Access (TA0001)(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 event.action == "exec" and host.os.type == "macos" and
    process.parent.name: (
      "Microsoft Word",
      "Microsoft Outlook",
      "Microsoft Excel",
      "Microsoft PowerPoint",
      "Microsoft OneNote"
    ) and
  process.name : (
    "curl",
    "nscurl",
    "bash",
    "sh",
    "osascript",
    "python*",
    "perl*",
    "mktemp",
    "chmod",
    "php",
    "nohup",
    "openssl",
    "plutil",
    "PlistBuddy",
    "xattr",
    "mktemp",
    "sqlite3",
    "funzip",
    "popen"
  ) and

  // Filter FPs related to product version discovery and Office error reporting behavior
  not process.args:
    (
      "ProductVersion",
      "hw.model",
      "ioreg",
      "ProductName",
      "ProductUserVisibleVersion",
      "ProductBuildVersion",
      "/Library/Application Support/Microsoft/MERP*/Microsoft Error Reporting.app/Contents/MacOS/Microsoft Error Reporting",
      "open -a Safari *",
      "defaults read *",
      "sysctl hw.model*",
      "ioreg -d2 -c IOPlatformExpertDevice *",
      "ps aux | grep 'ToDesk_Desktop' | grep -v grep",
      "PIPE=\"$CFFIXED_USER_HOME/.zoteroIntegrationPipe*"
    ) and

   not process.parent.executable :
        (
          "/Applications/ToDesk.app/Contents/MacOS/ToDesk_Service",
          "/usr/local/Privacy-i/PISupervisor",
          "/Library/Addigy/lan-cache",
          "/Library/Elastic/Agent/*",
          "/opt/jc/bin/jumpcloud-agent",
          "/usr/sbin/networksetup"
        ) and
   not (process.name : "sh" and process.command_line : "*$CFFIXED_USER_HOME/.zoteroIntegrationPipe*") and

   not process.Ext.effective_parent.executable : (
        "/Applications/ToDesk.app/Contents/MacOS/ToDesk_Service",
        "/usr/local/Privacy-i/PISupervisor",
        "/Library/Addigy/auditor",
        "/Library/Elastic/Agent/*",
        "/opt/jc/bin/jumpcloud-agent",
        "/usr/sbin/networksetup"
      )

Install detection rules in Elastic Security

Detect Suspicious macOS MS Office 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).