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Network Connection Initiated To Cloudflared Tunnels Domains

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.

MITRE ATT&CK

T1567 T1572

exfiltrationcommand-and-control

Detection Query

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

Author

Kamran Saifullah, Nasreddine Bencherchali (Nextron Systems)

Created

2024-05-27

Data Sources

windowsNetwork Connection Events

Platforms

windows

References

Tags

attack.exfiltrationattack.command-and-controlattack.t1567attack.t1572

Raw Content

title: Network Connection Initiated To Cloudflared Tunnels Domains
id: 7cd1dcdc-6edf-4896-86dc-d1f19ad64903
related:
    - id: a1d9eec5-33b2-4177-8d24-27fe754d0812
      type: derived
status: test
description: |
    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.
references:
    - https://defr0ggy.github.io/research/Abusing-Cloudflared-A-Proxy-Service-To-Host-Share-Applications/
    - https://www.guidepointsecurity.com/blog/tunnel-vision-cloudflared-abused-in-the-wild/
    - Internal Research
author: Kamran Saifullah, Nasreddine Bencherchali (Nextron Systems)
date: 2024-05-27
tags:
    - attack.exfiltration
    - attack.command-and-control
    - attack.t1567
    - attack.t1572
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Initiated: 'true'
        DestinationHostname|endswith:
            - '.v2.argotunnel.com'
            - 'protocol-v2.argotunnel.com'
            - 'trycloudflare.com'
            - 'update.argotunnel.com'
    condition: selection
falsepositives:
    - Legitimate use of cloudflare tunnels will also trigger this.
level: medium