Detect IDE Tunneling in Google Chronicle
Adversaries may abuse Integrated Development Environment (IDE) software with remote development features to establish an interactive command and control channel on target systems within a network. IDE tunneling combines SSH, port forwarding, file sharing, and debugging into a single secure connection, letting developers work on remote systems as if they were local. Unlike SSH and port forwarding, IDE tunneling encapsulates an entire session and may use proprietary tunneling protocols alongside SSH, allowing adversaries to blend in with legitimate development workflows. Some IDEs, like Visual Studio Code, provide CLI tools (e.g., code tunnel) that adversaries may use to programmatically establish tunnels and generate web-accessible URLs for remote access. These tunnels can be authenticated through accounts such as GitHub, enabling the adversary to control the compromised system via a legitimate developer portal.
MITRE ATT&CK
- Tactic
- Command and Control
- Technique
- T1219 Remote Access Tools
- Sub-technique
- T1219.001 IDE Tunneling
- Canonical reference
- https://attack.mitre.org/techniques/T1219/001/
YARA-L Detection Query
rule ide_tunneling_t1219_001 {
meta:
author = "Detection Engineering"
description = "Detects IDE tunneling (T1219.001) — adversaries abusing VS Code tunnel CLI, Microsoft devtunnel, JetBrains Gateway, Cursor, or Windsurf remote features to establish interactive C2 channels blending with legitimate developer workflows."
severity = "HIGH"
priority = "HIGH"
mitre_attack_tactic = "Command and Control"
mitre_attack_technique = "T1219.001"
mitre_attack_technique_name = "IDE Tunneling"
reference = "https://attack.mitre.org/techniques/T1219/001/"
version = "1.0"
events:
$e.metadata.event_type = "PROCESS_LAUNCH"
(
re.regex($e.target.process.file.full_path,
`(?i)(code\.exe|code-tunnel\.exe|code-insiders\.exe|code-tunnel|devtunnel\.exe|devtunnel|jetbrains-gateway\.exe|gateway\.exe|remote-dev-server\.sh|idea\.sh|pycharm\.sh|cursor\.exe|cursor|windsurf\.exe)$`)
or
re.regex($e.target.process.command_line,
`(?i)(\btunnel\b|--remote-tunnel|serve-web|dev-tunnel|--host\s+0\.0\.0\.0|--accept-server-license-terms|--no-browser|--provider\s+github)`)
)
condition:
$e
}Google Chronicle YARA-L 2.0 rule detecting IDE tunneling (T1219.001) via UDM PROCESS_LAUNCH events. Matches on known IDE tunnel binary names across Windows and Linux and command-line patterns for VS Code Remote Tunnels, devtunnel, JetBrains Gateway, Cursor, and Windsurf. Uses Chronicle's re.regex() function for flexible case-insensitive matching against UDM normalized fields.
Data Sources
Required Tables
False Positives & Tuning
- Sanctioned use of VS Code Remote Tunnels or JetBrains Gateway by developers in organizations that have explicitly approved cloud IDE tunneling as part of their remote work policy, particularly visible from known developer asset groups.
- Automated build systems or GitHub Actions runners invoking devtunnel or code-tunnel to create preview environments, where the initiating principal is a service account on a CI/CD host.
- Security operations analysts using IDE tunnel features to access isolated sandbox or malware analysis environments, where process launches originate from dedicated SOC workstations.
Other platforms for T1219.001
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1VS Code CLI Tunnel Initiation
Expected signal: Sysmon Event ID 1: Process Create with Image=code.exe, CommandLine containing 'tunnel --accept-server-license-terms --name test-tunnel'. Sysmon Event ID 22: DNS query for tunnels.api.visualstudio.com. If tunnel starts: Sysmon Event ID 3 for HTTPS connection to tunnel relay servers.
- Test 2DevTunnel CLI Tunnel Creation
Expected signal: Sysmon Event ID 1: Process Create with Image=devtunnel.exe, CommandLine containing 'host --port 8080 --allow-anonymous'. Sysmon Event ID 22: DNS query for devtunnels.ms. Sysmon Event ID 3: Network connection to Microsoft tunnel infrastructure.
- Test 3VS Code Tunnel Persistence via Scheduled Task
Expected signal: Security Event ID 4698: Scheduled task created with TaskContent containing 'code.exe tunnel'. Sysmon Event ID 1: Process Create for schtasks.exe with command line showing the tunnel command. The scheduled task itself won't execute (non-existent path) but the creation event fires.
References (8)
- https://attack.mitre.org/techniques/T1219/001/
- https://www.sentinelone.com/labs/operation-digital-eye-chinese-apt-compromises-critical-digital-infrastructure-via-visual-studio-code-tunnels/
- https://unit42.paloaltonetworks.com/stately-taurus-abuses-vscode-southeast-asian-espionage/
- https://medium.com/@truvis.thornton/visual-studio-code-embedded-reverse-shell-and-how-to-block-create-sentinel-detection-and-add-e864ebafaf6d
- https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/overview
- https://code.visualstudio.com/docs/remote/tunnels
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceprocessevents-table
- https://github.com/SigmaHQ/sigma/tree/master/rules/windows/process_creation
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