CVE-2021-33718 in Mendix
Summary
by MITRE • 07/13/2021
A vulnerability has been identified in Mendix Applications using Mendix 7 (All versions < V7.23.22), Mendix Applications using Mendix 8 (All versions < V8.18.7), Mendix Applications using Mendix 9 (All versions < V9.3.0). Write access checks of attributes of an object could be bypassed, if user has a write permissions to the first attribute of this object.
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Analysis
by VulDB Data Team • 07/16/2021
This vulnerability resides within the Mendix application platform's access control mechanisms, specifically affecting versions prior to the mentioned patches across Mendix 7, 8, and 9 branches. The flaw represents a critical authorization bypass issue that undermines the fundamental security model of the platform. When a user possesses write permissions to the first attribute of an object within a Mendix application, they can circumvent the normal access control checks that should govern their ability to modify other attributes of the same object. This creates a dangerous privilege escalation scenario where users can manipulate data beyond their intended permissions, effectively breaking the principle of least privilege that forms the cornerstone of secure application design.
The technical root cause of this vulnerability stems from improper implementation of attribute-level access controls within the Mendix runtime environment. The system fails to validate whether a user has appropriate write permissions for specific attributes when those attributes are not the first attribute of the object. This represents a classic case of insufficient authorization checks, which aligns with CWE-285 - "Improper Authorization" and CWE-345 - "Insufficient Verification of Data Authenticity." The vulnerability manifests because the platform's access control logic assumes that if a user can write to the first attribute, they should be able to write to all attributes, completely ignoring the granular permission model that administrators may have configured for individual attributes.
The operational impact of this vulnerability is severe and multifaceted across enterprise environments using Mendix applications. Attackers who gain access to accounts with write permissions to the first attribute of objects can potentially compromise sensitive data integrity throughout the application. This could lead to unauthorized data modification, information disclosure, and potential system compromise depending on the nature of the affected objects and their relationships within the application. The vulnerability affects all Mendix versions prior to the specified patches, meaning organizations running legacy applications are particularly at risk. The implications extend beyond simple data corruption, as this bypass could enable attackers to manipulate business logic, alter audit trails, or compromise the integrity of critical business processes that rely on proper access controls.
Organizations must prioritize immediate remediation of this vulnerability by upgrading to the patched versions of Mendix 7.23.22, 8.18.7, and 9.3.0 across all affected applications. Security teams should conduct comprehensive audits of their Mendix applications to identify and validate that all instances are properly patched, as this vulnerability could be exploited by both internal and external threat actors. The mitigation strategy should include implementing additional monitoring for unauthorized attribute modifications and conducting regular security assessments of Mendix applications to ensure that access control configurations are properly enforced. Organizations should also consider implementing network segmentation and access controls to limit exposure of Mendix applications to untrusted networks, following ATT&CK technique T1046 - "Network Service Scanning' and T1566 - "Phishing' to prevent initial compromise. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and proper access control configurations in enterprise application platforms, as it represents a fundamental failure in the platform's security architecture that could lead to significant data breaches and operational disruptions.