Suspicious Browser Child Process

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Identifies the execution of a suspicious browser child process. Adversaries may gain access to a system through a user visiting a website over the normal course of browsing. With this technique, the user’s web browser is typically targeted for exploitation.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

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:

  • Domain: Endpoint
  • OS: macOS
  • Use Case: Threat Detection
  • Tactic: Initial Access
  • Tactic: Execution
  • Data Source: Elastic Defend

Version: 105

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where host.os.type == "macos" and event.type in ("start", "process_started") and
  process.parent.name : ("Google Chrome", "Google Chrome Helper*", "firefox", "Opera", "Safari", "com.apple.WebKit.WebContent", "Microsoft Edge") and
  process.name : ("sh", "bash", "dash", "ksh", "tcsh", "zsh", "curl", "wget", "python*", "perl*", "php*", "osascript", "pwsh") and
  process.command_line != null and
  not process.command_line : "*/Library/Application Support/Microsoft/MAU*/Microsoft AutoUpdate.app/Contents/MacOS/msupdate*" and
  not process.args :
    (
      "hw.model",
      "IOPlatformExpertDevice",
      "/Volumes/Google Chrome/Google Chrome.app/Contents/Frameworks/*/Resources/install.sh",
      "--defaults-torrc",
      "*Chrome.app",
      "Framework.framework/Versions/*/Resources/keystone_promote_preflight.sh",
      "/Users/*/Library/Application Support/Google/Chrome/recovery/*/ChromeRecovery",
      "$DISPLAY",
      "*GIO_LAUNCHED_DESKTOP_FILE_PID=$$*",
      "/opt/homebrew/*",
      "/usr/local/*brew*"
    )

Framework: MITRE ATT&CKTM