Misconfigured Freemarker
TLDR: Misconfigured Freemarker, introduced in 1999, can lead to severe vulnerabilities such as code injection, cross-site scripting (XSS), and unintended data exposure. These issues often stem from improper input handling, insecure template configurations, and unsafe use of dynamic expressions, violating multiple OWASP Top Ten principles, including Input Validation, Output Encoding, and Access Controls.
https://freemarker.apache.org/
Improper input validation is a significant concern when using Freemarker. If unsanitized user inputs are allowed to populate templates, it can result in code injection or data manipulation, violating the OWASP Top Ten's recommendation for robust Input Validation practices.
https://owasp.org/www-community/Input_Validation
Disabling escaping mechanisms in Freemarker templates, such as by using the `?no_esc` directive, increases the risk of XSS attacks. By rendering unescaped content, developers open applications to malicious JavaScript injection, breaching the OWASP Top Ten's Output Encoding standards.
https://developer.mozilla.org/en-US/docs/Web/Security/Output_Encoding
Dynamic inclusion of templates in Freemarker without proper validation or access control can lead to unauthorized rendering of files or scripts. This misconfiguration highlights the importance of strict Access Controls and allowlists, aligning with OWASP Top Ten security principles.
https://freemarker.apache.org/docs/ref_directive_include.html
Directly exposing sensitive variables or configuration details in Freemarker templates without encryption increases the risk of data leakage. This behavior violates the OWASP Top Ten guidelines on secure Data Encryption and sensitive data handling practices.
https://owasp.org/www-community/Data_Encryption
Inadequate Error Handling in Freemarker templates can result in sensitive details, such as stack traces or debug messages, being displayed to users. Implementing proper error suppression and secure Error Handling is critical to meet the OWASP Top Ten standards.
https://owasp.org/www-community/Error_Handling
Over-reliance on Freemarker's Framework Defaults without tailoring configurations for specific applications can leave security gaps. Developers should review and adjust default settings to ensure compliance with OWASP Top Ten best practices.
https://owasp.org/www-community/Framework_Security_Project
Improper integration of Freemarker with API Endpoints without enforcing CORS or secure Cross-Domain Permissions can lead to unauthorized access or data exposure. Implementing strict Policy Enforcement measures is essential to secure such integrations.
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
Logging raw inputs or sensitive data in Freemarker templates without proper sanitization or encryption increases the risk of data exposure. Adopting secure Logging practices, such as masking sensitive information, is crucial to comply with OWASP Top Ten guidelines.
https://owasp.org/www-community/Logging_and_Monitoring_Cheat_Sheet
Failing to conduct regular dependency checking for Freemarker and its associated libraries can leave applications vulnerable to exploits targeting outdated components. Utilizing alerts for vulnerable components and automated dependency management is vital for maintaining security.
https://owasp.org/www-project-dependency-check/
Lastly, remote code execution (RCE) risks arise in Freemarker if untrusted inputs are executed within templates. Ensuring sandboxing of templates and validating all inputs is necessary to prevent such exploits, adhering to OWASP Top Ten's focus on secure template engine practices.