CVE-2024-45411 Overview
CVE-2024-45411 is a sandbox bypass vulnerability in Twig, the popular template language for PHP used extensively in Symfony applications. Under certain circumstances, the sandbox security checks fail to execute properly, allowing user-contributed templates to bypass the sandbox restrictions that are designed to prevent untrusted template code from performing dangerous operations.
The Twig sandbox feature is specifically designed to evaluate untrusted code safely by restricting access to potentially harmful functions, methods, and properties. When this protection mechanism is bypassed, attackers with the ability to submit template code can execute operations that should normally be blocked, potentially leading to unauthorized data access or system manipulation.
Critical Impact
This vulnerability allows attackers to bypass sandbox security restrictions in Twig templates, potentially enabling unauthorized code execution and data access in PHP applications that rely on Twig's sandbox for security isolation.
Affected Products
- Symfony Twig versions prior to 1.44.8
- Symfony Twig versions 2.x prior to 2.16.1
- Symfony Twig versions 3.x prior to 3.14.0
Discovery Timeline
- September 9, 2024 - CVE-2024-45411 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2024-45411
Vulnerability Analysis
This vulnerability represents a Protection Mechanism Failure (CWE-693), where the sandbox security checks that should protect against malicious template operations are not consistently executed. The Twig sandbox is a critical security feature that allows developers to safely render untrusted templates by restricting access to dangerous PHP functions, methods, and properties.
The sandbox bypass occurs under specific circumstances where the security policy enforcement is skipped, allowing templates to execute operations that would normally be blocked. This is particularly dangerous in multi-tenant applications, content management systems, or any environment where users can submit or modify Twig templates.
The vulnerability affects the network attack vector, meaning it can be exploited remotely without requiring authentication or user interaction. The scope is changed, indicating that the vulnerability can impact resources beyond the vulnerable component itself, potentially affecting the integrity of the broader application.
Root Cause
The root cause lies in incomplete security check enforcement within the Twig template rendering process. Under certain conditions, the sandbox security policy fails to intercept and validate template operations before execution. This allows malicious template code to bypass the restrictions that should prevent access to blocked functions, filters, methods, and properties defined in the sandbox policy.
The flaw specifically affects how Twig evaluates template expressions and method calls when the sandbox is enabled, creating a gap in the security enforcement mechanism that attackers can exploit.
Attack Vector
An attacker who can supply or modify Twig template content can craft malicious template code that exploits the sandbox bypass. The attack does not require any special privileges or authentication, and no user interaction is needed beyond the normal processing of the malicious template by the application.
Typical attack scenarios include:
- Multi-tenant applications where users can customize templates
- Content management systems with template editing capabilities
- Email templating systems that process user-supplied content
- Any application feature that allows user-contributed Twig templates
The vulnerability allows templates to call methods and access properties that the sandbox policy would normally block. This could enable attackers to execute arbitrary PHP code, access sensitive application data, or manipulate application state depending on the specific application context.
For technical details on the vulnerability mechanism, refer to the GitHub Security Advisory GHSA-6j75-5wfj-gh66.
Detection Methods for CVE-2024-45411
Indicators of Compromise
- Unusual template syntax or function calls in user-submitted Twig templates
- Template error logs showing attempts to access restricted methods or properties
- Unexpected application behavior when processing user-contributed templates
- Evidence of unauthorized data access or system modifications following template rendering
Detection Strategies
- Monitor application logs for Twig sandbox policy violations or unusual template processing errors
- Implement input validation to detect potentially malicious template constructs before processing
- Review audit logs for any changes to user-editable templates that contain suspicious syntax
- Deploy SentinelOne to detect post-exploitation activities that may result from successful sandbox bypasses
Monitoring Recommendations
- Enable detailed logging for Twig template compilation and rendering operations
- Set up alerts for template processing errors that may indicate exploitation attempts
- Monitor for unusual process spawning or file access patterns following template rendering
- Implement runtime application self-protection (RASP) to detect sandbox bypass attempts
How to Mitigate CVE-2024-45411
Immediate Actions Required
- Update Twig to patched versions: 1.44.8, 2.16.1, or 3.14.0 immediately
- Audit all locations where user-contributed templates are processed
- Review and restrict template capabilities to the minimum required functionality
- Consider temporarily disabling user template features until patches are applied
Patch Information
Symfony has released patches for all affected version branches. The fixes are available in the following commits:
Update via Composer:
# Update Twig to the latest patched version
composer update twig/twig
# Or specify minimum version requirements
composer require "twig/twig:^3.14.0"
Debian users should refer to the Debian LTS Security Announcement for distribution-specific updates.
Workarounds
- Disable user-contributed template functionality until patches can be applied
- Implement additional server-side validation of template content before processing
- Use a strict allowlist of permitted template syntax and reject any templates containing unauthorized constructs
- Consider rendering user templates in an isolated environment with minimal privileges
# Example: Update Twig via Composer
composer update twig/twig --with-all-dependencies
# Verify installed version
composer show twig/twig | grep version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
