Misconfigured Jinja2
TLDR: Misconfigured Jinja2, introduced in 2008, can lead to critical vulnerabilities such as remote code execution (RCE), data exposure, and cross-site scripting (XSS). These misconfigurations often result from improper handling of inputs, templates, and default settings, violating multiple OWASP Top Ten principles, including Input Validation, Output Encoding, and Access Controls.
https://jinja.palletsprojects.com/
Improper input validation in Jinja2 templates creates a significant security risk. Unsanitized user inputs passed directly into templates may allow attackers to inject malicious code or tamper with rendered outputs. This misconfiguration violates the OWASP Top Ten's emphasis on ensuring robust Input Validation mechanisms.
https://owasp.org/www-community/Input_Validation
The use of the `
}` or disabling autoescaping, increasing the risk of XSS. This highlights the need for proper Output Encoding to ensure that dynamic content does not execute unintended JavaScript or HTML in the browser, aligning with the OWASP Top Ten recommendations.
https://developer.mozilla.org/en-US/docs/Web/Security/Output_Encoding
Over-reliance on Jinja2's Framework Defaults can expose applications to exploitation. Developers often assume that default behaviors provide adequate protection, but these defaults may not align with specific security requirements. Proper customization of Jinja2's settings is crucial to avoid misconfigurations.
https://owasp.org/www-community/Framework_Security_Project
Dynamic template imports and inclusion in Jinja2 without validation can lead to unauthorized rendering of templates. This scenario underscores the importance of strict Access Controls and allowlists to prevent the inclusion of malicious or untrusted template files, as per the OWASP Top Ten.
https://jinja.palletsprojects.com/en/3.0.x/templates/#include
Exposing sensitive variables or data in Jinja2 templates without proper encryption or access restrictions increases the risk of data breaches. This misstep violates OWASP Top Ten principles on Data Encryption and secure data handling practices.
https://owasp.org/www-community/Data_Encryption
The absence of proper Error Handling in Jinja2 templates can reveal sensitive application information, such as template paths or configuration details. Suppressing debug messages and masking stack traces are essential to comply with the OWASP Top Ten guidelines on secure Error Handling.
https://owasp.org/www-community/Error_Handling
Integrating Jinja2 templates with API Endpoints without enforcing strict CORS policies or Cross-Domain Permissions can create security gaps. Attackers could exploit these vulnerabilities to execute unauthorized requests, contravening OWASP Top Ten recommendations on Policy Enforcement.
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
Insecure integration of Jinja2 with external libraries or dependencies often leads to outdated or vulnerable components being used. Adopting dependency checking tools and keeping libraries updated is crucial to aligning with the OWASP Top Ten's focus on secure dependency management.
https://owasp.org/www-project-dependency-check/
Lastly, developers should ensure that logging of sensitive data in Jinja2 templates is avoided. Logging unfiltered or sensitive variables can lead to data exposure and compliance issues, emphasizing the OWASP Top Ten's best practices on secure Logging and monitoring.
https://owasp.org/www-community/Logging_and_Monitoring_Cheat_Sheet