Development

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Development Environment

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Adding Commands

• Create a new folder with the name of the command in Payload_Type/poseidon/poseidon/agent_code/[COMMAND].
• Inside the folder create a single go file called command.go. If the implementation of the command is compatible with both macOS and Linux, only a single go file should be necessary.
  • If the implementation is different, create two additional files. All files that are for the darwin/macOS implementation should have the nomenclature command_darwin.go and command_linux.go for Linux. There are a minimum set of imports that are required for any command.

import (
	"github.com/MythicAgents/poseidon/Payload_Type/poseidon/agent_code/pkg/utils/structs"
)

• The results/output for a command should be saved to a Response struct.
• The Completed status should be set
• The Status should be set to error if you’re erroring out of the task for some reason
• Send the resulting message out to Mythic via task.Job.SendResponses channel

func Run(task structs.Task) {
	msg := task.NewResponse()
	msg.UserOutput = "test output"
	msg.Completed = true
	task.Job.SendResponses <- msg
	return
}

• Now that the command is created, it needs to be part of the executing switch statement. Add it to “Payload_Type/poseidon/agent_code/pkg/tasks/newTasking.go” as part of the switch statement based on the command name and be sure to import it at the top.

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Adding C2 Profiles

• Add C2 profile code to the Payload_Types/poseidon/pkg/profiles/ folder in file name that matches the profile (e.g., http.go or websocket.go)
• Create a structure that will hold the configuration for your profile. Your C2 structure/profile should conform to the Profile interface defined in Payload_Types/poseidon/agent_code/pkg/profiles/profile.go
• C2 profile parameters are passed in at build time using Go’s -X ldflags options which only sets string variables
  • Create package-level string variables for each C2 profile configurable option (e.g., var USER_AGENT string)
  • Create an init() function that converts the string variables to the desired format, build the profile structure, and register the new struct RegisterAvailableC2Profile(&profile).
• The C2 profile must be specified as a build condition at the top of the go file (e.g., // +build http). This ensures only the selected C2 profile is compiled into the agent
• If you’re creating a new P2P profile, then make sure to also create the corresponding file in Payload_Types/poseidon/agent_code/pkg/utils/p2p/ for your P2P profile.
  • This additional file will also have an init function that registers a new instance of a struct (registerAvailableP2P(poseidonTCP{})) that satisfies the structs.P2PProcessor interface.
  • This additional functionality makes it so that non-p2p agents can still connect to and communicate with your p2p profiles (ex: an http payload can still link to a poseidon_tcp even though it’s not binding to a port and listening).