MacOS Installer Package Spawns Network Eventedit

Detects the execution of a MacOS installer package with an abnormal child process (e.g bash) followed immediately by a network connection via a suspicious process (e.g curl). Threat actors will build and distribute malicious MacOS installer packages, which have a .pkg extension, many times imitating valid software in order to persuade and infect their victims often using the package files (e.g pre/post install scripts etc.) to download additional tools or malicious software. If this rule fires it should indicate the installation of a malicious or suspicious package.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • macOS
  • Threat Detection
  • Execution
  • Command and Control

Version: 101

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

sequence by host.id, user.id with maxspan=30s
[process where event.type == "start" and event.action == "exec" and process.parent.name : ("installer", "package_script_service") and process.name : ("bash", "sh", "zsh", "python", "osascript", "tclsh*")]
[network where event.type == "start" and process.name : ("curl", "osascript", "wget", "python")]

Framework: MITRE ATT&CKTM