CVE-2021-40352 in OpenEMR
Summary
by MITRE • 09/01/2021
OpenEMR 6.0.0 has a pnotes_print.php?noteid= Insecure Direct Object Reference vulnerability via which an attacker can read the messages of all users.
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Analysis
by VulDB Data Team • 12/24/2024
The vulnerability identified as CVE-2021-40352 affects OpenEMR version 6.0.0 and represents a critical Insecure Direct Object Reference flaw in the pnotes_print.php script. This vulnerability allows unauthorized attackers to access private messages intended for other users by manipulating the noteid parameter in the URL. The flaw stems from insufficient input validation and access control mechanisms within the application's object reference handling system, creating a direct pathway for privilege escalation through improper object access validation.
The technical implementation of this vulnerability occurs when the application processes the noteid parameter without adequate authorization checks or user context validation. An attacker can simply modify the noteid value in the URL to access notes belonging to different users, bypassing the normal authentication and authorization controls that should prevent such cross-user data access. This represents a classic indirect object reference vulnerability where the application fails to verify that the requesting user has legitimate access rights to the requested resource. The vulnerability is particularly dangerous as it operates at the application logic level, where the system's access control mechanisms are fundamentally flawed, allowing for unauthorized data disclosure across user boundaries.
The operational impact of this vulnerability extends beyond simple data exposure, creating significant privacy and security concerns for healthcare environments that rely on OpenEMR for patient information management. Attackers can potentially access sensitive medical records, personal health information, and confidential communications between healthcare providers and patients. This vulnerability directly violates the principle of least privilege and could lead to compliance violations under healthcare regulations such as HIPAA, as it enables unauthorized access to protected health information. The impact is compounded by the fact that this vulnerability affects the messaging functionality, which often contains critical clinical information and personal details that could be exploited for identity theft, insurance fraud, or other malicious activities.
Organizations using OpenEMR 6.0.0 should immediately implement mitigations including input validation for the noteid parameter, proper access control enforcement, and user context verification before processing object references. The recommended approach involves implementing proper authorization checks that verify the requesting user's relationship to the requested note before allowing access. This vulnerability aligns with CWE-284, which describes improper access control, and maps to ATT&CK technique T1213.002 for data from information repositories. Organizations should also consider implementing additional security controls such as rate limiting for API endpoints, logging and monitoring of access patterns, and regular security assessments to identify similar indirect object reference vulnerabilities in other application components. The remediation should include updating to a patched version of OpenEMR or implementing proper access control mechanisms that validate user permissions before granting access to sensitive data objects.