What are dynamic parameters?

Sometimes when creating a command, the options you present to the operator might not always be static. For example, you might want to present them with a list of files that have been download; you might want to show a list of processes to choose from for injection; you might want to reach out to a remote service and display output from there. In all of these scenarios, the parameter choices for a user might change. Mythic can now support this.

Where are dynamic parameters?

Since we're talking about a command's arguments, all of this lives in your Command's class that subclasses TaskArguments. Let's take an augmented shell example:

class ShellArguments(TaskArguments):
    def __init__(self, command_line):
        super().__init__(command_line)
        self.args = {
            "command": CommandParameter(
                name="command", type=ParameterType.String, description="Command to run"
            ),
            "files": CommandParameter(name="files", type=ParameterType.ChooseOne, default_value=[],
                                      dynamic_query_function=self.get_my_files)
        }
​
    async def get_my_files(self, callback: dict) -> [str]:
        resp = await MythicRPC().execute("get_file", callback_id=callback["id"], max_results=-1, filename=".*")
        return [r["filename"] for r in resp.response]
​
    async def parse_arguments(self):
        if len(self.command_line) > 0:
            if self.command_line[0] == "{":
                self.load_args_from_json_string(self.command_line)
            else:
                self.add_arg("command", self.command_line)
        else:
            raise ValueError("Missing arguments")

Here we can see that the files CommandParameter has an extra component - dynamic_query_function. This parameter points to a function that also lives within the same class, get_my_files in this case. This function is a little different than the other functions in the Command file because it occurs before you even have a task - this is generating parameters for when a user does a popup in the user interface. As such, this function gets one parameter - a dictionary of information about the callback itself. It should return an array of strings that will be presented to the user.

You have access to a lot of the same RPC functionality here that you do in create_tasking, but except for one notable exception - you don't have a task yet, so you have to do things based on the callback_id. You won't be able to create/delete entries via RPC calls, but you can still do pretty much every query capability. In this example, we're doing a get_file query to pull all files that exist within the current callback and present their filenames to the user.

Accessible Info from Dynamic Function

What information do you have at your disposal during this dynamic function call? Via the dictionary parameter passed to your function (i.e. callback in the previous example), you have access to the following:

• build_parameters - this key provides all of the build parameters used to generate the payload that this current callback generated from

• c2info - this is an array of dictionaries of the different c2 profiles built into the callback. Just like Payload Type Info where you iterate over them, you can do the same here. For example, to see a parameter called "callback_host" in our first c2 profile is callback.c2info[0]['callback_host'].

• agent_callback_id - id that agents see for the callback

• init_callback - time of first checkin

• last_checkin = time of last checkin

• user = user context for the callback

• host = hostname of the callback

• pid = pid of the callback

• ip = internal ip of the callback

• external_ip = external ip of the callback

• process_name = name of the process that this callback is in

• description = description of the callback

• operator = operator that created the payload for this callback

• active = p.BooleanField(constraints=[p.SQL("DEFAULT TRUE")], null=False)

• registered_payload = UUID of the payload associated with this callback

• integrity_level = integrity level of the callback (0 to 4)

• os = os value associated with the callback

• architecture =architecture of the callback

• domain = domain of the callback

• extra_info = if the agent is storing extra information, it's here (this is a custom, free-form field for agents to use)

• sleep_info = sleep information for the callback that agents can set

• id - the database ID of the callback that you can use in RPC calls