OpenCanary Application Logs: Nmap FIN Scan Targeting (Logtype 5005)

Detects Nmap FIN scan targeting against an OpenCanary node using application logs with logtype 5005.

FreeReviewedSigma · High · v5

Product: opencanary
Category: application
Author: Marco Pedrinazzi (@pedrinazziM) (SigmaHQ), DRL 1.1
Published: 2026-01-06
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 flags OpenCanary instances where the service records activity consistent with an Nmap FIN scan targeting the node. FIN scans are a common reconnaissance technique used to probe network services while attempting to evade more conspicuous scan signatures. Detection relies on OpenCanary application telemetry indicating the specific event logged as logtype 5005.

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)

OpenCanary Application Logs: Nmap FIN Scan Targeting (Logtype 5005)

Pivot detection · T1046 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
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.

opencanary-nmap-fin-scan-targeting-detection-application-logtype-5005-eae8c0c8

title: "OpenCanary Application Logs: Nmap FIN Scan Targeting (Logtype 5005)"
id: bfb7c413-36e6-423d-be7f-90587fcfc018
status: experimental
description: This rule flags OpenCanary instances where the service records activity consistent with an Nmap FIN scan targeting the node. FIN scans are a common reconnaissance technique used to probe network services while attempting to evade more conspicuous scan signatures. Detection relies on OpenCanary application telemetry indicating the specific event logged as logtype 5005.
references:
  - https://opencanary.readthedocs.io/en/latest/starting/configuration.html#services-configuration
  - https://github.com/thinkst/opencanary/blob/a0896adfcaf0328cfd5829fe10d2878c7445138e/opencanary/logger.py#L52
  - https://github.com/SigmaHQ/sigma/blob/master/rules/application/opencanary/opencanary_portscan_nmap_fin_scan.yml
author: Marco Pedrinazzi (@pedrinazziM), Huntrule Team
date: 2026-01-06
tags:
  - attack.discovery
  - attack.t1046
logsource:
  category: application
  product: opencanary
detection:
  selection:
    logtype: 5005
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: eae8c0c8-e5da-450a-9d7d-66aa56cd26b6
    type: derived

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