Websocket Profile Updates

[sysophost]

In a bid to make the Websocket C2 profile more robust I have added support for multiple callback hosts (similar to HTTPX) and added handling logic for this in Poseidon.

This differs from the multiple callback hosts implemented in HTTPX which can rotate hosts for every request, callback host rotation is only used at the time the initial websocket connection is established or any time there is a connection retry. The callback hosts array can be manually rotated/updated via the update_c2 command in Poseidon for running agents.

Changes

• Replaced callback_host and callback_port with callback_hosts which consumes an array of hosts in the format ws[s]://foo.bar[:8080] to attempt for callback connections.
• Added domain_rotation_method to dictate how callback domains are selected from callback_hosts (currently this is fall-back or random)
• Added domain_rotation_delay to define a delay in seconds between attempts to communicate with callback domains.
• Added domain_rotation_failure_threshold to define a failure threshold, i.e number of allowed failures for a given callback domain before it is removed from callback_hosts.
• Replaced USER_AGENT and domain_front with headers which provides an array for custom headers. Currently this defaults to including user-agent and host but any other headers can be specified here.
• Replaced ENDPOINT_REPLACE with endpoint this is literally just a rename of this param to align with the rest of the params.

Future Plans

Update endpoint to perform similarly to callback_hosts to support multiple endpoints. This would ideally use something akin to domain_rotation_method to provide multiple methods for selecting an endpoint.

Right now these are maintained in private forks of Websocket and Poseidon due to the number of breaking changes this introduces. At some point I would like to make these changes available to merge.