Sigma rule: Network Connection Initiated To Cloudflared Tunnels Domains

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-bbbc06452e93, updated 2024-05-27T00:00:00.000Z.

Rule

Title
Network Connection Initiated To Cloudflared Tunnels Domains
Status
test
Level
medium
Author
Kamran Saifullah, Nasreddine Bencherchali (Nextron Systems)
Date
2024-05-27
File
rules/windows/network_connection/net_connection_win_domain_cloudflared_communication.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects network connections to Cloudflared tunnels domains initiated by a process on the system.
Attackers can abuse that feature to establish a reverse shell or persistence on a machine.

Log source

product
windows
category
network_connection

Detection

selection:
    Initiated: 'true'
    DestinationHostname|endswith:
        - '.v2.argotunnel.com'
        - 'protocol-v2.argotunnel.com'
        - 'trycloudflare.com'
        - 'update.argotunnel.com'
condition: selection

False positives (as the rule lists them)

  • Legitimate use of cloudflare tunnels will also trigger this.

Tags

  • attack.exfiltration
  • attack.command-and-control
  • attack.t1567
  • attack.t1572

MITRE ATT&CK ids this rule names

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_domain_cloudflared_communication.yml

Sources and licences

  • SigmaHQ

    "Network Connection Initiated To Cloudflared Tunnels Domains" by Kamran Saifullah, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_domain_cloudflared_communication.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Network Connection Initiated To Cloudflared Tunnels Domains",
entity page, dataset version ref-bbbc06452e93, updated 2024-05-27T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/7cd1dcdc-6edf-4896-86dc-d1f19ad64903 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 7cd1dcdc-6edf-4896-86dc-d1f19ad64903, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.