Command and Control (C2) Daemon¶
The C2 daemon is a service that listens to the command line client on a pair of named pipes. The client submits a command and its arguments to be run. The daemon executes the command and returns the output.
The command line client and the daemon communicate by transferring CBOR encoded data inside of CSP packets. This allows for a dynamic protocol and for simple passing of messages with varying data payloads.
These messages are passed between a client and the daemon. A client will initiate a C2 “command transaction” by issuing a request. A transaction is comprised of a command request which is processed by the command daemon and completed when the daemon returns a response.
Daemon Input Message Format¶
The daemon accepts a CSP packet containing an encoded CBOR payload with the following fields:
|MSG_TYPE||Int||Designates the command type|
|ARG_COUNT||Int||The number of arguments following the command|
|COMMAND_NAME||String||The command to be run|
|ARGS||Array||An array of argument values|
Daemon Output Message Format¶
Upon a successful command request processing and execution the daemon will respond with a CSP packet containing an encoded CBOR payload with the following fields:
|RETURN_CODE||Int||The return code of the command that was run|
|EXEC_TIME||Double||The amount of time that the command took to run|
|OUTPUT||String||The stdout of the command that was run|
If there is an error that occurs while processing a command request, the daemon will return an error packet containing the following fields:
|MSG_TYPE||Int||Designates the response type|
|ERROR_MSG||Int||The description of the error that occurred|