OpenCanary - NMAP NULL Scan — Sigma Rule

Rule metadata and linked tags

Author: Marco Pedrinazzi (@pedrinazziM). Source status: experimental; severity: high. Source dates: 2026-01-06 / not supplied.

{
  "category": "application",
  "product": "opencanary"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 66eb6ffb7452e9dccff21a2703d04c28387c2076f96598e1604195ef78bf2e4b

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: OpenCanary - NMAP NULL Scan
id: 68b8547b-107f-43f3-97fb-900a7d63c190
status: experimental
description: Detects instances where an OpenCanary node has been targeted by a NMAP NULL Scan
references:
    - https://opencanary.readthedocs.io/en/latest/starting/configuration.html#services-configuration
    - https://github.com/thinkst/opencanary/blob/a0896adfcaf0328cfd5829fe10d2878c7445138e/opencanary/logger.py#L52
author: Marco Pedrinazzi (@pedrinazziM)
date: 2026-01-06
tags:
    - attack.discovery
    - attack.t1046
logsource:
    category: application
    product: opencanary
detection:
    selection:
        logtype: 5003
    condition: selection
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://opencanary.readthedocs.io/en/latest/starting/configuration.html#services-configuration
• https://github.com/thinkst/opencanary/blob/a0896adfcaf0328cfd5829fe10d2878c7445138e/opencanary/logger.py#L52