Windows Potential Cloudflared Network Connection
Description
This analytic detects network connection events possibly associated with the Cloudflared tool, a tool used to create tunnels via Cloudflare. Cloudflared is functionally very similar to ngrok, an ingress-as-a-service tool. It reaches out to the Cloudflare Edge Servers, creating an outbound connection over HTTPS(HTTP2/QUIC), where the tunnel's controller makes services or private networks accessible.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
values(All_Traffic.src_port) as src_port
from datamodel=Network_Traffic.All_Traffic where
All_Traffic.dest_port=7844
BY All_Traffic.action All_Traffic.app All_Traffic.dest
All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.direction
All_Traffic.dvc All_Traffic.protocol All_Traffic.protocol_version
All_Traffic.src All_Traffic.src_ip All_Traffic.transport
All_Traffic.user All_Traffic.vendor_product
| `drop_dm_object_name(All_Traffic)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_potential_cloudflared_network_connection_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
- Some legitimate use cases include authorized tunneling for remote access or service exposure in enterprise environments. Filter alerts for approved Cloudflared deployments to reduce false positives.
Analyst notes
Known false positives: Some legitimate use cases include authorized tunneling for remote access or service exposure in enterprise environments. Filter alerts for approved Cloudflared deployments to reduce false positives.