DNS Query To Visual Studio Code Tunnels Domain — Sigma Rule

Rule metadata and linked tags

Author: citron_ninja. Source status: test; severity: medium. Source dates: 2023-10-25 / 2023-11-20.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 33d6d7770e9a886902b97be6d98ec59b3e68c1f9c74dd59ecc2ca99510955d4a

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: DNS Query To Visual Studio Code Tunnels Domain
id: b3e6418f-7c7a-4fad-993a-93b65027a9f1
related:
    - id: 9501f8e6-8e3d-48fc-a8a6-1089dd5d7ef4 # Net Connection DevTunnels
      type: similar
    - id: 4b657234-038e-4ad5-997c-4be42340bce4 # Net Connection VsCode
      type: similar
    - id: 1cb0c6ce-3d00-44fc-ab9c-6d6d577bf20b # DNS DevTunnels
      type: similar
status: test
description: |
    Detects DNS query requests to Visual Studio Code tunnel domains. 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: citron_ninja
date: 2023-10-25
modified: 2023-11-20
tags:
    - attack.command-and-control
    - attack.t1071.001
logsource:
    product: windows
    category: dns_query
detection:
    selection:
        QueryName|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