macOS System Network Connection Discovery via who, w, last, lsof, or netstat

Flags macOS process executions of who/w/last/lsof/netstat used to discover network or session information.

FreeReviewedSigma · Informational · v2

Product: macos
Category: process_creation
Author: Daniil Yugoslavskiy, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-19
Updated: 2026-07-31

ATT&CK techniques

Discovery

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
- T1049System Network Connections Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies process executions on macOS where the command image name ends with one of: /who, /w, /last, /lsof, or /netstat. These utilities are commonly used to enumerate system users and active network connections, which can support discovery and reconnaissance prior to further activity. It relies on process creation telemetry capturing the process image path for the executed command.

Reporting behind it

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macOS System Network Connection Discovery via who, w, last, lsof, or netstat

Pivot detection · T1049 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

macos-system-network-connections-discovery-via-who-w-last-lsof-netstat-9a7a0393

title: macOS System Network Connection Discovery via who, w, last, lsof, or netstat
id: 3a183ea3-1a95-42e6-ba1d-dd4926490bed
status: test
description: "This rule identifies process executions on macOS where the command image name ends with one of: /who, /w, /last, /lsof, or /netstat. These utilities are commonly used to enumerate system users and active network connections, which can support discovery and reconnaissance prior to further activity. It relies on process creation telemetry capturing the process image path for the executed command."
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1049/T1049.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/macos/process_creation/proc_creation_macos_system_network_connections_discovery.yml
author: Daniil Yugoslavskiy, oscd.community, Huntrule Team
date: 2020-10-19
modified: 2022-12-28
tags:
  - attack.discovery
  - attack.t1049
logsource:
  category: process_creation
  product: macos
detection:
  selection:
    Image|endswith:
      - /who
      - /w
      - /last
      - /lsof
      - /netstat
  condition: selection
falsepositives:
  - Legitimate activities
level: informational
license: DRL-1.1
related:
  - id: 9a7a0393-2144-4626-9bf1-7c2f5a7321db
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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