macOS Network Service Enumeration via nc, netcat, nmap, or telnet

Flags macOS executions of nc/netcat, nmap, or telnet consistent with local or remote service enumeration.

FreeReviewedSigma · Low · v2

Product: macos
Category: process_creation
Author: Alejandro Ortuno, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-21
Updated: 2026-07-31

ATT&CK techniques

Discovery

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
- T1046Network Service Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies process execution on macOS where the binary name ends with nc or netcat (and includes nmap or telnet). Such tools are commonly used to enumerate local or remote network services during discovery, which can help attackers map reachable systems and ports. The detection relies on process creation telemetry, matching the executed Image name suffix and applying a command-line substring exclusion to reduce noise.

Reporting behind it

Related detections9 linkedT1046 — drag to rearrange

Suspicious Fscan Internal Network Scanner Execution (via process_creation)

Possible Network Service Scanning via Nmap or Masscan (via process_creation)

Malicious Anonymous Login - Domain Specified (via security)

Suspicious Network Scanning Tool Execution

Malicious RDP Discovery Performed on Multiple Hosts (via rdp)

Malicious Anonymous Access Performed to Multiple Targets (via security)

Malicious Network Login Performed to Multiple Targets (via security)

Suspicious SoftPerfect Network Scanner Execution for Discovery

Suspicious SoftPerfect Network Scanner Execution (via process_creation)

macOS Network Service Enumeration via nc, netcat, nmap, or telnet

Pivot detection · T1046 · 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-network-service-enumeration-via-nc-netcat-nmap-or-telnet-84bae5d4

title: macOS Network Service Enumeration via nc, netcat, nmap, or telnet
id: aa27ea65-d03f-4eb6-98a1-cdfedb826dcb
status: test
description: This rule identifies process execution on macOS where the binary name ends with nc or netcat (and includes nmap or telnet). Such tools are commonly used to enumerate local or remote network services during discovery, which can help attackers map reachable systems and ports. The detection relies on process creation telemetry, matching the executed Image name suffix and applying a command-line substring exclusion to reduce noise.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1046/T1046.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/macos/process_creation/proc_creation_macos_network_service_scanning.yml
author: Alejandro Ortuno, oscd.community, Huntrule Team
date: 2020-10-21
modified: 2021-11-27
tags:
  - attack.discovery
  - attack.t1046
logsource:
  category: process_creation
  product: macos
detection:
  selection_1:
    Image|endswith:
      - /nc
      - /netcat
  selection_2:
    Image|endswith:
      - /nmap
      - /telnet
  filter:
    CommandLine|contains: l
  condition: (selection_1 and not filter) or selection_2
falsepositives:
  - Legitimate administration activities
level: low
license: DRL-1.1
related:
  - id: 84bae5d4-b518-4ae0-b331-6d4afd34d00f
    type: derived

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