CVE-2024-45411: Twig Sandbox Security Bypass Vulnerability and Its Impact on Web Applications

Twig is a widely used template language for PHP, allowing developers to separate the presentation layer (HTML, CSS, JavaScript) from the logic layer (PHP). This separation is crucial for maintaining a clean codebase and enhancing security. However, a recently discovered vulnerability (CVE-2024-45411) has allowed user-contributed templates to bypass important sandbox security restrictions under certain circumstances. In this article, we will discuss the vulnerability in detail, its implications, and how to fix it.

Vulnerability Details

Twig allows developers to implement a sandbox mode to restrict the execution of potentially dangerous code within user-generated templates. The sandbox is an essential security feature, primarily when user-generated content is allowed within a web application. Unfortunately, under specific scenarios, the sandbox security checks may be bypassed.

This security bypass vulnerability, with the CVE identifier CVE-2024-45411, affects the following versions:

Impact

The vulnerability may allow an attacker to execute arbitrary code within the context of the web application, potentially leading to unauthorized access, data exfiltration, or even server compromise. As a result, web application security may be severely compromised.

Code Snippet

The following example demonstrates a simplified user-contributed template that attempts to access a restricted function (shell_exec) by bypassing the sandbox security checks:

{% set foo = "shell_exec" %}
{% set bar = "ls -la" %}
{{ foo(bar) }}

Under normal circumstances, the sandbox should prevent the execution of the dangerous shell_exec function. However, due to the vulnerability (CVE-2024-45411), the security checks can be bypassed, potentially allowing the attacker to execute arbitrary commands.

The vulnerability has been documented by the following sources

- CVE-2024-45411 - National Vulnerability Database (NVD)
- Twig GitHub Security Advisory
- Symfony Security Release: twig/twig (v1.44.8, v2.16.1, v3.14.)

How to Fix the Vulnerability

To address CVE-2024-45411, developers must upgrade their Twig installations to one of the following versions:

Upgrading can be done using Composer

# For Twig 1.x users
composer require twig/twig:1.44.8

# For Twig 2.x users
composer require twig/twig:2.16.1

# For Twig 3.x users
composer require twig/twig:3.14.

After upgrading your Twig installation, ensure that all user-contributed templates are thoroughly tested to prevent potential security risks.

Conclusion

The Twig sandbox security bypass vulnerability (CVE-2024-45411) is a critical issue that highlights the importance of staying current with software updates. Developers must be vigilant in patching their dependencies and thoroughly testing their applications to maintain security and integrity. By upgrading your Twig installation accordingly, you can mitigate the risks associated with this vulnerability and keep your web applications secure.

Timeline

Published on: 09/09/2024 19:15:13 UTC
Last modified on: 09/10/2024 12:09:50 UTC