Definition
The detection of an internal host relaying traffic between the internal network and the external network.
How it works
A relay may use a variety of proxying, forwarding, or routing technologies to bridge a protected network with an external network. A defensive analytic to detect a relay network may compare the network sessions among multiple hosts. Hosts which have nearly similar network statistics may be part of a relay network. The statistics may include number of bytes sent to and from, time of session initiation, packet size, or packet arrival time data.
Considerations
Complex intranet VPNs or routing encapsulation may affect the detection analytics. In addition, unwanted packets might not be forwarded, and additional packets may be added at the relay, further complicating detection.
Implementation perspective
Relay Pattern Analysis should be treated as a technical defensive capability rather than a product checkbox. In practice, teams should define the protected scope, the conditions under which the technique acts, and the observable evidence that demonstrates the intended behavior. For this technique, likely engineering context includes Outbound Internet Network Traffic.
Use the technique to identify suspicious, unauthorized, or abnormal activity through observable evidence and repeatable analysis.
Questions to ask
- Which events, states, or artifacts must be observed for the analysis to work?
- What analytic logic, threshold, comparison, or signature turns observations into a finding?
- How are expected false positives, blind spots, and environmental variations documented?
- Who receives the result, and what action is expected when the technique produces a finding?
Evidence and validation
- Telemetry and data-source configuration records
- Analytic logic, thresholds, signatures, and version history
- Test cases demonstrating expected positive and negative results
- Alert, triage, escalation, and tuning records
Common failure patterns
- Required telemetry is missing, delayed, or transformed in a way that invalidates the analysis.
- The technique produces alerts without an accountable triage and response process.
- Detection coverage is claimed from product deployment without testing the relevant analytic behavior.
This implementation perspective is original Bare Metal Cyber educational content. It does not replace the official D3FEND definition or establish that a specific product implements the technique.
Technique hierarchy
Top-level family
Parent techniques
Direct child techniques
None listed at this level.
Artifacts and ontology entities
These relationships describe how D3FEND connects a defensive technique to artifacts or other ontology entities. They describe graph semantics, not a product certification.
Explicit technique relationships
Show inferred artifact relationship paths (1)
Offensive-technique relationships
These relationships are generated from D3FEND graph paths and are explicitly experimental. They should be treated as hypotheses for defensive analysis—not as proof that the technique prevents, detects, or removes an offensive behavior.
ATT&CK Enterprise (30)
ATT&CK for ICS (1)
Authoritative sources
- Open this technique on the official D3FEND website ↗
- Open the official ontology resources ↗
- Malicious relay detection on networks ↗VECTRA NETWORKS Inc · Ryan James PRENGER; Nicolas BEAUCHESNE; Karl Matthew LYNN · PatentReference
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by The MITRE Corporation. MITRE D3FEND™ and the D3FEND logo are trademarks of The MITRE Corporation. MITRE ATT&CK® and ATT&CK® are registered trademarks of The MITRE Corporation. Use of D3FEND source material is subject to the official Terms of Use.