OpenCanary Application Logs: Detect SYN Port Scan Targets on a Hosted Node

Flags OpenCanary events indicating the host was probed with a TCP SYN port scan.

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 identifies when an OpenCanary node is targeted by a TCP SYN port scan, based on application logs indicating scan activity (logtype 5001). SYN scanning is a common discovery technique used to enumerate open ports quickly before further exploitation. The detection relies on OpenCanary application telemetry that records the scan-related event type.

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: Detect SYN Port Scan Targets on a Hosted Node

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-application-telemetry-syn-port-scan-targeting-a-host-974be8d2

title: "OpenCanary Application Logs: Detect SYN Port Scan Targets on a Hosted Node"
id: 527b7d7d-130c-44ce-9397-081ed5b0560a
status: experimental
description: This rule identifies when an OpenCanary node is targeted by a TCP SYN port scan, based on application logs indicating scan activity (logtype 5001). SYN scanning is a common discovery technique used to enumerate open ports quickly before further exploitation. The detection relies on OpenCanary application telemetry that records the scan-related event type.
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_syn_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: 5001
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: 974be8d2-283e-4033-ab08-7505b84204d0
    type: derived

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