CVE-2016-20006 in REST-JSON Project
Summary
by MITRE • 01/01/2021
The REST/JSON project 7.x-1.x for Drupal allows blockage of user logins, 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 • 07/14/2026
The REST/JSON project version 7.x-1.x for Drupal presents a significant security vulnerability that enables unauthorized users to block legitimate user logins, classified as SA-CONTRIB-2016-033. This vulnerability specifically affects the contrib module ecosystem rather than core Drupal functionality, which means it operates outside of Drupal's official security advisory policy framework. The issue stems from improper access control mechanisms within the REST/JSON implementation that fails to adequately validate user permissions when processing authentication requests. When exploited, this flaw allows malicious actors to manipulate the system's authentication flow and effectively prevent legitimate users from accessing their accounts.
The technical nature of this vulnerability aligns with CWE-284 Access Control Issues, specifically manifesting as improper access control during authentication processes. The REST/JSON module likely implements a flawed permission checking mechanism that does not properly verify whether incoming requests originate from authorized users or malicious actors attempting to disrupt service availability. This weakness creates an opportunity for denial of service attacks where attackers can systematically block user logins through carefully crafted API calls or JSON requests that exploit the module's authentication bypass mechanisms.
The operational impact of this vulnerability extends beyond simple authentication disruption, as it represents a critical threat to system availability and user access. When legitimate users encounter blocked login attempts, they experience service degradation that can escalate into complete system unusability depending on the scale of the attack. The vulnerability's contribution to the broader ATT&CK framework falls under the T1499 technique for Network Denial of Service, where attackers leverage application-level weaknesses to compromise system accessibility. Organizations relying on this contrib module may face unauthorized access disruptions that could affect business operations and user productivity.
Mitigation strategies for this vulnerability require immediate attention and comprehensive security measures beyond simple patching due to the module's contrib status. Administrators should implement network-level firewalls to restrict access to REST endpoints, particularly those handling authentication functions. The recommended approach involves disabling or removing the vulnerable REST/JSON module from production environments until a secure version is available, as this represents the most effective immediate protection against exploitation. Additionally, organizations should conduct thorough security assessments of all contrib modules in their Drupal installations and establish monitoring protocols to detect unusual login patterns that might indicate attempted exploitation of similar access control weaknesses. Given that this vulnerability operates outside Drupal's official security advisory policy, proactive security measures become even more critical for maintaining system integrity and user access availability.