5up3rc / merlin

Merlin is a cross-platform post-exploitation HTTP/2 Command & Control server and agent written in golang.

Merlin (BETA)

Merlin is a cross-platform post-exploitation HTTP/2 Command & Control  server and agent written in golang.

An introductory blog post can be found here: https://medium.com/@Ne0nd0g/introducing-merlin-645da3c635a

Getting Started

The quickest and easiest way to start using Merlin is download the pre-compiled binary files found in the Releases section. The files are compressed into 7z archives and are password protected to prevent Anti-Virus inspection when downloading. The password is merlin.

Install GO

In order to run Merlin from source, or to compile Merlin yourself, the Go programing language must be installed on the system. However, if you just want to run a pre-compiled version, you do not need to install Go.

Download and install GO: https://golang.org/doc/install

Download Merlin Server

It is recommended to download the compiled binaries from the Releases section

Ensure your GOPATH environment variable is set

Download Merlin with Go

go get github.com/Ne0nd0g/merlin

If you want to use git instead of Go, merlin must be in your GOPATH i.e. $GOPATH/src/github.com/Ne0nd0g/merlin

cd $GOPATH/src/github.com/Ne0nd0g;git clone https://github.com/Ne0nd0g/merlin/

Run Merlin Server

Merlin Server can be run as a script or compiled and run as a standalone binary file.

go run cmd/merlinserver/main.go

Compile Merlin Server

Compile Merlin into an executable using Make make server-windows or make server-linux or make server-darwin

Merlin Server Usage

  -debug
        Enable debug output
  -i string
        The IP address of the interface to bind to (default "0.0.0.0")
  -p int
        Merlin Server Port (default 443)
  -v    Enable verbose output
  -x509cert string
        The x509 certificate for the HTTPS listener (default "C:\\Merlin\\data\\x509\\server.crt")
  -x509key string
        The x509 certificate key for the HTTPS listener (default "C:\\Merlin\\data\\x509\\server.key")

Merlin Server Commands

Merlin is equipped with a tab completion system that can be used to see what commands are available at any given time. Hit double tab to get a list of all available commands.

Name	Description
agent	Interact with agents or list agents
banner	Print the Merlin banner
exit	Exit and close the Merlin server
help	Print help screen
interact	Interact with an agent. Alias for Empire users
quit	Exit and close the Merlin server
sessions	List all agents session information. Alias for MSF users
use	Use a function of Merlin (i.e modules)
version	Print the Merlin server version
?	Print help screen
*	Anything else will be execute on the host operating system

Agent Commands

These are the commands to control an agent from the server. Tab completion can be used to select an Agent's identifier.

Name	Description
cmd	Execute a command on the agent", "cmd ping -c 3 8.8.8.8"
back	Return to the main menu
download	Download a file from the agent
exit	Exit and close the Merlin server
help	Print help screen
info	Display all information about the agent
kill	Instruct the agent to die or quit
main	Return to the main menu
quit	Exit and close the Merlin server
set	Set the value for one of the agent's options (maxretry, padding, skew, sleep)
show	Show information about a module or its options (show options or show info)
upload	Upload a file to the agent
?	Print help screen
*	Anything else will be execute on the host operating system

Module Commands

These are the commands to configure and execute a module. Tab completion can be used to select options and agents.

Name	Description
back	Return to the main menu
exit	Exit and close the Merlin server
help	Print help screen
main	Return to the main menu
quit	Exit and close the Merlin server
run	Run or execute the module
set	Set the value for one of the module's options
show	Show information about a module or its options (show options or show info)
?	Print help screen
*	Anything else will be execute on the host operating system

TLS Certificates

By default, Merlin will load server.crt and server.key from the data/x509/ directory. You must generate your own certificate pair and place them in this directory.

Third Party Libraries

The 3rd party libraries used with Merlin are kept in the vendor directory. This project will default to using the library files in that folder.

Running Merlin Agent

The agent portion of Merlin should be run as a compiled binary file on a target host.

It is recommended to download the compiled binaries from the Releases section

Ensure your GOPATH environment variable is set!

Compile Merlin Agent into an executable

make agent-windows or make agent-linux or make agent-darwin

Merlin Agent can also be compiled without Make, using just go. To compile Merlin Agent with your hard coded Merlin Server's address, so it doesn't have to specified on the command line, include -ldflags -X main.url=https://acme.com:443/

Example: go build -o merlinagent.exe -ldflags "-X main.url=https://acme.com:443/" cmd/merlinagent/main.go

Run Merlin Agent as script: go run cmd/merlinagent/main.go

USAGE

  -debug
        Enable debug output
  -sleep duration
        Time for agent to sleep (default 10s)
  -skew int
        Variable time skew for agent to sleep
  -url string
        Full URL for agent to connect to (default "https://127.0.0.1:443")
  -v    Enable verbose output