CVE-2019-3966 in OpenEMR
Summary
by MITRE
In OpenEMR 5.0.1 and earlier, controller.php contains a reflected XSS vulnerability in the foreign_id parameter. This could allow an attacker to execute arbitrary code in the context of a user's session.
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Analysis
by VulDB Data Team • 11/27/2023
The vulnerability identified as CVE-2019-3966 represents a critical reflected cross-site scripting flaw within the OpenEMR medical records system version 5.0.1 and earlier. This issue resides in the controller.php file where the foreign_id parameter fails to properly sanitize user input before processing. The flaw allows attackers to inject malicious scripts that are then executed within the context of authenticated user sessions, potentially compromising the entire system. OpenEMR is a widely deployed electronic medical records system used by healthcare providers globally, making this vulnerability particularly concerning from a security perspective.
The technical nature of this vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications. The reflected XSS occurs when the application receives data from an untrusted source and immediately includes that data in a web page without proper validation or encoding. In this case, the foreign_id parameter serves as the attack vector where malicious input can be injected and subsequently reflected back to the user's browser. The vulnerability's severity is amplified because it operates within a medical records system where users have elevated privileges and access to sensitive patient data. Attackers can leverage this flaw to steal session cookies, perform actions on behalf of users, or redirect victims to malicious sites that can further exploit the compromised session.
The operational impact of this vulnerability extends beyond simple script execution as it fundamentally undermines the security model of the OpenEMR system. When an attacker successfully exploits this vulnerability, they can execute arbitrary code within the user's browser session, potentially gaining access to patient records, modifying medical data, or even executing administrative functions. This represents a significant threat to healthcare data integrity and patient privacy, particularly in environments where OpenEMR is used for sensitive medical information handling. The vulnerability can be exploited through various means including phishing emails, compromised websites, or social engineering attacks that trick users into clicking malicious links containing the exploit payload.
Security professionals should consider this vulnerability in the context of the ATT&CK framework where it maps to techniques such as T1059.007 for scripting and T1566 for phishing attacks. Organizations using OpenEMR should implement immediate mitigations including input validation and output encoding for all parameters in the controller.php file, particularly the foreign_id parameter. The most effective defense involves implementing proper parameter sanitization and validation to ensure that any user input is thoroughly checked before being processed or displayed. Additionally, organizations should deploy web application firewalls to detect and block malicious requests, implement strict content security policies, and ensure regular security updates are applied. The vulnerability underscores the critical importance of maintaining up-to-date medical software systems and implementing comprehensive security monitoring to detect potential exploitation attempts.