CVE-2016-20002 in REST-JSON Project
Summary
by MITRE • 01/01/2021
The REST/JSON project 7.x-1.x for Drupal allows comment access bypass, aka SA-CONTRIB-2016-033. NOTE: This project is not covered by Drupal's security advisory policy.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability identified as SA-CONTRIB-2016-033 represents a critical authentication and authorization flaw within the REST/JSON module for Drupal version 7.x, specifically affecting the development branch 1.x. This issue stems from an improper implementation of access control mechanisms that govern how external applications interact with comment data via the JSON API interface. In standard web application architecture, particularly those built on frameworks like Drupal, it is imperative that all entry points enforce consistent security policies regardless of whether they are accessed through a traditional browser-based frontend or an automated programmatic interface such as REST. The flaw in this module allows unauthenticated users to bypass these restrictions, effectively treating the API endpoint with less scrutiny than standard page requests. This discrepancy creates a significant gap in the application's defense-in-depth strategy, allowing attackers who lack valid credentials to perform actions that should be restricted to authenticated and authorized individuals.
From a technical perspective, the root cause lies in the module's failure to properly invoke or respect Drupal’s core access control hooks when processing REST requests for comment entities. Typically, systems rely on role-based access control lists to determine if a user has permission to view, create, update, or delete specific resources. In this instance, the JSON endpoint likely defaults to allowing public access or fails to validate session tokens and permissions before rendering data. This oversight means that sensitive information embedded within comments can be retrieved by anyone with knowledge of the API endpoints, without needing to log in first. The vulnerability is particularly dangerous because REST APIs are often designed for machine-to-machine communication where automated scripts can rapidly iterate through available resources, making bulk extraction of data feasible and efficient compared to manual scraping techniques used against traditional web pages.
The operational impact of this access bypass is substantial, primarily centering on the compromise of confidentiality and potentially integrity depending on further exploitation vectors. Attackers can harvest private user comments which may contain personally identifiable information such as email addresses, physical locations discussed in text, or other sensitive personal data shared within community forums or internal corporate sites running Drupal. This exposure violates fundamental privacy principles and regulatory compliance requirements such as GDPR or HIPAA if applicable to the organization's domain. Furthermore, because REST APIs are often integrated with third-party applications, this vulnerability could serve as an initial foothold for more complex attacks. An adversary might use the exposed data to craft targeted phishing campaigns against specific users identified in the comments, thereby escalating from a simple information disclosure issue to a broader social engineering attack vector that threatens organizational security posture.
This flaw aligns closely with CWE-284 Improper Access Control and CWE-798 Use of Hard-coded Credentials if authentication mechanisms were bypassed via default configurations rather than just missing checks. It also maps directly to the MITRE ATT&CK technique T1078 Valid Accounts, as it allows unauthorized entities to operate under the guise of valid access without possessing actual credentials. The fact that this project is not covered by Drupal’s official security advisory policy highlights a critical risk for organizations relying on contributed modules outside the core distribution's support lifecycle. Users must recognize that third-party extensions often undergo less rigorous peer review and may lack timely patches, making proactive monitoring essential.
To mitigate this vulnerability, administrators should immediately disable or uninstall the REST/JSON module if it is not strictly required for their specific use case. If continued usage is necessary due to legacy integrations, applying any available community-provided patches that enforce proper access checks on JSON endpoints is critical. Organizations must also implement robust input validation and output encoding practices across all API layers to ensure consistency in security enforcement. Additionally, deploying a Web Application Firewall can provide an additional layer of defense by detecting anomalous traffic patterns associated with automated enumeration attacks against the REST interface. Regular audits of contributed modules for adherence to Drupal’s coding standards and security best practices are essential to prevent similar access control failures in other parts of the application stack.