Windows Devtunnels Image Loaded
Description
Detects image load events associated with Microsoft Devtunnels usage. Microsoft Devtunnels is a feature within Visual Studio that allows developers to expose their local development environment to the internet via secure, temporary tunnels, enabling external access for testing webhooks, APIs, and other services. While designed for legitimate development purposes, an attacker could exploit this feature to expose a compromised system or service to the internet, creating a covert communication channel that bypasses network security measures. By using Dev Tunnels, the attacker can establish a remote connection to the compromised environment, facilitate data exfiltration, or maintain command-and-control communications while avoiding detection by blending their activities with legitimate development traffic.
Query · spl
`sysmon`
EventID=7
ImageLoaded="*\\AppData\\Local\\Temp\\.net\\devtunnel\\*"
ImageLoaded="*devtunnel.dll"
| fillnull
| stats count min(_time) as firstTime
max(_time) as lastTime
by Computer ImageLoaded EventID loaded_file loaded_file_path process_exec process_guid
process_hash process_id process_name process_path service_dll_signature_exists
service_dll_signature_verified signature_id user_id vendor_product
| rename Computer as dest
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_devtunnels_image_loaded_filter`
Implementation guide
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known false positives
- Legitimate developers using Microsoft Devtunnels for testing and debugging may trigger this detection. Filter alerts for approved development environments and personnel.
Analyst notes
Known false positives: Legitimate developers using Microsoft Devtunnels for testing and debugging may trigger this detection. Filter alerts for approved development environments and personnel.