Twig PHP Server Side Template Injection Scanner

Twig PHP is a templating engine used widely in web applications for generating HTML output from templates and data sources. Developed by SensioLabs, it is often integrated with PHP-based frameworks like Symfony to facilitate dynamic content creation. Twig PHP is favored for its simplicity and powerful features, making it a popular choice among developers for customizing and producing web pages. The software is commonly implemented in content management systems, e-commerce platforms, and any custom PHP-based web applications for rendering views. Its usage spans across small personal projects to large enterprise-level applications, providing developers with extensive control over presentation logic. Twig PHP's template engine simplifies the separation of presentation from logic, enhancing code maintainability and responsiveness.

The Server Side Template Injection (SSTI) vulnerability allows attackers to exploit the template engine to execute unauthorized commands or scripts on the server. This happens when unsanitized input from users is embedded into templates, leading to potential execution of arbitrary commands. Such vulnerabilities are critical because they enable attackers to compromise the application entirely, accessing sensitive data or gaining administrative control. In the context of Twig PHP, this vulnerability can be particularly dangerous due to the extensive access it might provide across various integrated web services. The ease with which SSTI can be exploited makes it a high-severity issue, prompting immediate and robust mitigation measures. Organizations must ensure template engines like Twig PHP are configured and implemented securely to avoid such vulnerabilities.

SSTI vulnerabilities in Twig PHP stem from improper validation and sanitization of user inputs that are incorporated into templates. The vulnerable endpoint in the Twig PHP SSTI scenario is the search functionality, which processes user-submitted queries. Specifically, the parameter 'search_key' is susceptible when it incorporates user input directly within the template logic without adequate checks. Attack strings such as certain mathematical expressions can be injected by attackers to test the vulnerability. The exploitation involves crafting commands which, when executed, reveal sensitive information or disrupt service functionalities. Proper usage validation, escaping of commands, and employing strict input handling measures are essential to prevent such malicious exploitations within Twig PHP applications.

If exploited, the SSTI vulnerability could allow an attacker to execute arbitrary code, leading to unauthorized data access and manipulation. The possible effects of this are severe, including data breaches, exposure of sensitive information, and potential corruption of application integrity. Furthermore, an exploit could give attackers administrative control over the application, enabling them to manipulate or damage the system at will. Beyond individual application impacts, these vulnerabilities could extend to other network resources integrated with the infected application. Mitigating SSTI vulnerabilities is critical to prevent any loss of data confidentiality, integrity, and availability within the affected systems.

REFERENCES

• https://twig.symfony.com/doc/2.x/