Network Connection Initiated To Visual Studio Code Tunnels Domain — Sigma Rule

Rule metadata and linked tags

Author: Kamran Saifullah. Source status: test; severity: medium. Source dates: 2023-11-20 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 031628e13dbf799dabaf5870d581666d47d50bf2082b7fc8eaeac0d384b5abdf

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: Network Connection Initiated To Visual Studio Code Tunnels Domain
id: 4b657234-038e-4ad5-997c-4be42340bce4
related:
    - id: 9501f8e6-8e3d-48fc-a8a6-1089dd5d7ef4 # Net Connection DevTunnels
      type: similar
    - id: b3e6418f-7c7a-4fad-993a-93b65027a9f1 # DNS VsCode
      type: similar
    - id: 1cb0c6ce-3d00-44fc-ab9c-6d6d577bf20b # DNS DevTunnels
      type: similar
status: test
description: |
    Detects network connections to Visual Studio Code tunnel domains initiated by a process on a system. Attackers can abuse that feature to establish a reverse shell or persistence on a machine.
references:
    - https://ipfyx.fr/post/visual-studio-code-tunnel/
    - https://badoption.eu/blog/2023/01/31/code_c2.html
    - https://cydefops.com/vscode-data-exfiltration
author: Kamran Saifullah
date: 2023-11-20
tags:
    - attack.exfiltration
    - attack.command-and-control
    - attack.t1567
    - attack.t1572
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Initiated: 'true'
        DestinationHostname|endswith: '.tunnels.api.visualstudio.com'
    condition: selection
falsepositives:
    - Legitimate use of Visual Studio Code tunnel will also trigger this.
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate use of Visual Studio Code tunnel will also trigger this.

Source references

• https://ipfyx.fr/post/visual-studio-code-tunnel/
• https://badoption.eu/blog/2023/01/31/code_c2.html
• https://cydefops.com/vscode-data-exfiltration