Misconfigured Handlebars.js
TLDR: Misconfigured Handlebars.js, introduced in 2010, often leads to severe vulnerabilities such as code injection, data exposure, and improper input sanitization. These issues arise from insufficient understanding of template engine best practices, violating several OWASP Top Ten principles including Input Validation, Output Encoding, and Access Controls.
Improper input sanitization in Handlebars.js is a primary vulnerability. If user inputs are directly embedded into templates without validation, it allows malicious payloads to execute, resulting in remote code execution (RCE). This violates OWASP Top Ten guidance on Input Validation and secure template engine usage.
https://owasp.org/www-community/Input_Validation
Failing to escape dynamic content in templates is another critical issue with Handlebars.js. By default, Handlebars.js escapes HTML, but using raw helpers such as `
}` bypasses this protection, enabling cross-site scripting (XSS) attacks. This breaches the OWASP Top Ten's emphasis on Output Encoding.
https://developer.mozilla.org/en-US/docs/Web/Security/Output_Encoding
The use of untrusted or improperly sanitized helpers in Handlebars.js templates increases risks of data leakage or unauthorized actions. For instance, dynamic helpers without security checks can expose sensitive data, violating the OWASP Top Ten’s Access Controls best practices.
https://owasp.org/www-community/Access_Control
Default settings in Handlebars.js may not always align with secure coding practices. Over-reliance on these Framework Defaults without additional safeguards can leave applications exposed to exploitation. The OWASP Top Ten recommends customizing default configurations to align with specific application requirements.
https://owasp.org/www-community/Framework_Security_Project
Improper use of partials in Handlebars.js templates can also introduce vulnerabilities. Dynamic loading of partials without proper input validation or allowlists may enable attackers to inject malicious content. This misconfiguration highlights the importance of adhering to OWASP Top Ten's Sanitization Routines.
https://handlebarsjs.com/partials.html
Handling external data sources improperly in Handlebars.js templates often leads to violations of Data Encryption and Key Management principles. Exposing sensitive data or using insecure methods to retrieve it increases risks of data breaches, which the OWASP Top Ten categorically warns against.
https://owasp.org/www-community/Data_Encryption
Errors or debug data rendered in Handlebars.js templates can reveal sensitive application details, violating the OWASP Top Ten's Error Handling guidelines. It is crucial to suppress stack traces and prevent logging of sensitive information in production environments.
https://owasp.org/www-community/Error_Handling
The improper integration of Handlebars.js with APIs can create gaps in Cross-Domain Permissions and CORS policies. If templates fail to restrict cross-origin access or validate API inputs, they violate OWASP Top Ten's Policy Enforcement recommendations.
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
Regular dependency checking and alerts for vulnerable components are essential when using Handlebars.js. Outdated or compromised libraries can introduce security vulnerabilities, reinforcing the OWASP Top Ten's emphasis on proactive maintenance and security updates.
https://owasp.org/www-project-top-ten/OWASP_Top_Ten_2017/A6_2017-Security_Misconfiguration