Elastic Security Detection Rules

Suspicious Installer Package Spawns Network Event

Last updated 14 days ago on 2025-04-21
Created 4 years ago on 2021-02-23

About

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.
Tags
Domain: EndpointOS: macOSUse Case: Threat DetectionTactic: ExecutionTactic: Command and ControlData Source: Elastic DefendLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Execution (TA0002)(opens in a new tab or window)

↳ Command and Scripting Interpreter (T1059)(opens in a new tab or window)

Command and Control (TA0011)(opens in a new tab or window)

↳ Application Layer Protocol (T1071)(opens in a new tab or window)

False Positive Examples
Custom organization-specific macOS packages that use .pkg files to run cURL could trigger this rule. If known behavior is causing false positives, it can be excluded from the rule.
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.network*logs-endpoint.events.process*
Related Integrations

endpoint(opens in a new tab or window)

Query
sequence by host.id, process.entity_id with maxspan=15s
[process where host.os.type == "macos" and event.type == "start" and event.action == "exec" and process.parent.name like~ ("installer", "package_script_service") and ((process.name in ("bash", "sh", "zsh") and process.args == "-c") or (process.name like~ ("python*", "osascript", "tclsh*", "curl", "nscurl")))]
[network where host.os.type == "macos" and event.type == "start"]

Install detection rules in Elastic Security

Detect Suspicious Installer Package Spawns Network Event 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).