Protocol Tunneling T1572
Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.
Events covered
19 catalog events are tagged with this technique by at least one rule.
Authoring guide
Patterns shared across the 54 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.
Fields filtered most (28 distinct)
The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.
Top indicator values (195 distinct)
Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.
Exclusions (3 distinct)
Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.
Rules under this technique
Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.
Sigma 24 rules
- Cloudflared Tunnel Connections Cleanup
- Cloudflared Tunnel Execution
- Cloudflared Tunnels Related DNS Requests
- Communication To LocaltoNet Tunneling Service Initiated
- Communication To Ngrok Tunneling Service Initiated
- DNS Query To Devtunnels Domain
- Network Connection Initiated To BTunnels Domains
- Network Connection Initiated To Cloudflared Tunnels Domains
- Network Connection Initiated To DevTunnels Domain
- Network Connection Initiated To Visual Studio Code Tunnels Domain
- Port Forwarding Activity Via SSH.EXE
- Potential RDP Tunneling Via Plink
- Potential RDP Tunneling Via SSH
- Potentially Suspicious Usage Of Qemu
- Process Initiated Network Connection To Ngrok Domain
- PUA - 3Proxy Execution
- PUA - Ngrok Execution
- RDP Over Reverse SSH Tunnel
- RDP to HTTP or HTTPS Target Ports
- RDP tunneling configuration enabled for port forwarding
- RDP tunneling via ngrok detected
- Silence.EDA Detection
- Suspicious Plink Port Forwarding
- Tunneling Tool Execution
Elastic 5 rules
- Port Forwarding Rule Addition
- Potential DNS Tunneling via NsLookup
- Potential Protocol Tunneling via Cloudflared
- Potential Protocol Tunneling via Yuze
- Potential Remote Desktop Tunneling Detected
Splunk 23 rules
- Named Pipe Created (Sysmon)
- ngrok Execution - Windows (PowerShell)
- ngrok Execution - Windows (Sysmon)
- ngrok Execution - Windows (Windows Event Log)
- Ngrok Reverse Proxy on Network
- Potential ngrok Tunnel - Windows (Windows Event Log)
- QEMU Network Tunneling - Windows (PowerShell)
- QEMU Network Tunneling - Windows (Sysmon)
- QEMU Network Tunneling - Windows (Windows Event Log)
- Scheduled Task with Potential SSH Tunnel - Windows (PowerShell)
- Scheduled Task with Potential SSH Tunnel - Windows (Sysmon)
- Scheduled Task with Potential SSH Tunnel - Windows (Windows Event Log)
- ssh.exe Execution (Sysmon)
- ssh.exe Execution (Windows Event Log)
- Tunneling Process Created (PowerShell)
- Tunneling Process Created (Sysmon)
- Tunneling Process Created (Windows Event Log)
- Windows Ngrok Reverse Proxy Usage
- Windows Potential Cloudflared Network Connection
- Windows Potential Cloudflared Tunnel Execution
- Windows Protocol Tunneling with Plink
- Windows SoftEther VPN Masquerading as Legitimate Binary
- Windows SSH Proxy Command