Styx is a reference architecture for placing MQTT relay bridges between an agent fleet and a private Mythic MQTT broker.
An agent can be configured with several public relay endpoints. Each relay is an MQTT bridge that forwards traffic over a private overlay network to one private broker. Mythic's MQTT C2 profile connects to that broker.
agent
|-- TLS --> relay A -- private overlay --> private MQTT broker <-- Mythic MQTT profile
|-- TLS --> relay B -- private overlay --> /
`-- TLS --> relay C -- private overlay --> /
The relay list gives the agent alternative ingress paths.
- Architecture — component boundaries and traffic flow.
- Deployment guidance — provider-neutral planning and validation guidance.
- Security considerations — trade-offs and controls to apply in an implementation.
- Illustrative bridge configuration — a deliberately incomplete example, not a ready-to-run configuration.
Use this repository to reason about the design, then implement it within your own operational environment and change-control process.