Cloudflared Tunnel Connections Cleanup — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2023-05-17 / 2023-12-21.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f4d04862beb209e1406e71e3b738bdb049a8933d3f5e2f892e9626e0d5e44174

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: Cloudflared Tunnel Connections Cleanup
id: 7050bba1-1aed-454e-8f73-3f46f09ce56a
status: test
description: Detects execution of the "cloudflared" tool with the tunnel "cleanup" flag in order to cleanup tunnel connections.
references:
    - https://github.com/cloudflare/cloudflared
    - https://developers.cloudflare.com/cloudflare-one/connections/connect-apps
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-17
modified: 2023-12-21
tags:
    - attack.command-and-control
    - attack.t1102
    - attack.t1090
    - attack.t1572
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - ' tunnel '
            - 'cleanup '
        CommandLine|contains:
            - '-config '
            - '-connector-id '
    condition: selection
falsepositives:
    - Legitimate usage of Cloudflared.
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate usage of Cloudflared.

Source references

• https://github.com/cloudflare/cloudflared
• https://developers.cloudflare.com/cloudflare-one/connections/connect-apps