6. Dynamic Command Parameter Values

Dynamic command parameters let a payload type calculate the choices shown to an operator when a tasking modal opens. Use them when the valid values depend on callback state, another parameter, Mythic data, or an external service. Dynamic queries run before a task exists. They can query Mythic by callback, but cannot use task-scoped RPC calls.

Define a query

Set dynamic_query_function on a ChooseOne or ChooseMultiple command parameter. The function receives a PTRPCDynamicQueryFunctionMessage and returns a PTRPCDynamicQueryFunctionMessageResponse.

class ShellArguments(TaskArguments):
    def __init__(self, command_line, **kwargs):
        super().__init__(command_line, **kwargs)
        self.args = {
            "command": CommandParameter(
                name="command",
                type=ParameterType.String,
                description="Command to run",
            ),
            "file": CommandParameter(
                name="file",
                type=ParameterType.ChooseOne,
                dynamic_query_function=self.get_executables,
            ),
        }

    async def get_executables(
        self, input_msg: PTRPCDynamicQueryFunctionMessage
    ) -> PTRPCDynamicQueryFunctionMessageResponse:
        file_result = await SendMythicRPCFileSearch(
            MythicRPCFileSearchMessage(
                CallbackID=input_msg.Callback,
                LimitByCallback=False,
                Filename="",
            )
        )

        if not file_result.Success:
            return PTRPCDynamicQueryFunctionMessageResponse(
                Success=False,
                Error=file_result.Error,
            )

        requested_suffix = input_msg.OtherParameters.get("suffix", ".exe")
        choices = sorted(
            {
                entry.Filename
                for entry in file_result.Files
                if entry.Filename.endswith(requested_suffix)
            }
        )
        return PTRPCDynamicQueryFunctionMessageResponse(
            Success=True,
            Choices=choices,
        )

    async def parse_arguments(self):
        if not self.command_line:
            raise ValueError("Missing arguments")
        if self.command_line[0] == "{":
            self.load_args_from_json_string(self.command_line)
        else:
            self.add_arg("command", self.command_line)

OtherParameters contains the current values of the other fields in the modal. This lets one dynamic choice depend on an earlier operator selection.

Request fields

The request contains:

Python field	JSON field	Purpose
`Command`	`command`	Command whose modal is open
`ParameterName`	`parameter_name`	Parameter requesting choices
`PayloadType`	`payload_type`	Payload type of the callback
`CommandPayloadType`	`command_payload_type`	Payload type that owns the command, including augmentation containers
`Callback`	`callback`	Internal callback ID for RPC calls
`CallbackDisplayID`	`callback_display_id`	Operation-scoped callback ID shown in the UI
`AgentCallbackID`	`agent_callback_id`	Callback UUID known to the agent
`PayloadOS`	`payload_os`	OS selected for the backing payload
`PayloadUUID`	`payload_uuid`	UUID of the backing payload
`Secrets`	`secrets`	Secrets available to the requesting operator
`OtherParameters`	`other_parameters`	Current values from the rest of the modal

Return Success=True and a Choices list. Return Success=False with Error when the choices could not be generated. An empty successful list means there are currently no valid choices. Mythic 4.0 also supports dynamic queries for payload build parameters and C2 profile parameters. Those definitions can return complex choices with separate stored and display values. See Dynamic Build Parameters and C2 Profile Parameters.

​Define a query

​Request fields

​Related dynamic parameters

Define a query

Request fields

Related dynamic parameters