Detection: Windows Potential Cloudflared Tunnel Execution

Updated Date: 2026-04-13 ID: 2e29b58e-0f5a-42fc-b435-0fdce8862831 Author: Raven Tait, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

This analytic detects command-line arguments associated with the cloudflared client used to create Cloudflare tunnels. Cloudflared is functionally very similar to ngrok, an ingress-as-a-service tool. Cloudflared reaches out to the Cloudflare Edge Servers, creating an outbound connection over HTTPS(HTTP2/QUIC), where the tunnel's controller makes services or private networks accessible.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5
 6from datamodel=Endpoint.Processes where
 7
 8Processes.process="*tunnel*"
 9(
10    (
11        Processes.process="*run*"
12        Processes.process="*token*"
13    )
14    OR
15    (
16        Processes.process="*--url*"
17        Processes.process="*localhost*"
18    )
19)
20
21by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
22   Processes.parent_process_name Processes.parent_process_exec Processes.action
23   Processes.dest Processes.process_current_directory Processes.process_path
24   Processes.process_integrity_level Processes.original_file_name Processes.parent_process
25   Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
26   Processes.process_guid Processes.process_id Processes.user Processes.process_name
27
28
29| `drop_dm_object_name(Processes)`
30
31| `security_content_ctime(firstTime)`
32
33| `security_content_ctime(lastTime)`
34
35| `windows_potential_cloudflared_tunnel_execution_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	Other	`'crowdstrike:events:sensor'`	`'crowdstrike'`
Sysmon EventID 1	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`
Windows Event Log Security 4688	Windows	`'XmlWinEventLog'`	`'XmlWinEventLog:Security'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_potential_cloudflared_tunnel_execution_filter	`search *`

windows_potential_cloudflared_tunnel_execution_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1572	Protocol Tunneling	Command And Control

Command and Control

DE.AE

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Risk Event	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Some legitimate use cases include authorized DevOps or IT teams using Cloudflared for secure remote access and network management. Filter alerts based on approved usage and trusted users.

Associated Analytic Story

Reverse Network Proxy

Risk Based Analytics (RBA)

Risk Message:

Potential Cloudflared tunnel execution observed on $dest$ via $process$.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	50	parent_process_name

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1