CVE-2021-25922 in OpenEMR
Summary
by MITRE • 03/23/2021
In OpenEMR, versions 4.2.0 to 6.0.0 are vulnerable to Reflected Cross-Site-Scripting (XSS) due to user input not being validated properly. An attacker could trick a user to click on a malicious url and execute malicious code.
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Analysis
by VulDB Data Team • 04/03/2021
The vulnerability identified as CVE-2021-25922 affects OpenEMR versions ranging from 4.2.0 through 6.0.0, representing a critical reflected cross-site scripting flaw that exposes the medical records management system to potential cyber attacks. This vulnerability resides in the application's insufficient input validation mechanisms, which fail to properly sanitize user-provided data before processing and returning it to web browsers. The flaw enables attackers to inject malicious scripts into web pages viewed by other users, creating a persistent threat vector that can compromise the integrity of the entire system.
The technical implementation of this vulnerability stems from the application's failure to adequately filter and escape user input parameters within HTTP requests. When OpenEMR processes incoming data without proper validation, it allows malicious payloads to be reflected back to users through web responses, particularly in contexts such as error messages, search results, or parameter handling. This weakness directly aligns with CWE-79, which defines cross-site scripting vulnerabilities as the failure to properly neutralize user input data within the application's output. The reflected nature of this attack means that the malicious script must be delivered through a crafted URL that, when clicked by an unsuspecting user, executes the malicious code within the victim's browser context.
The operational impact of this vulnerability extends beyond simple data theft, as it creates multiple attack vectors that can be leveraged by threat actors to escalate their compromise. An attacker could craft malicious URLs containing JavaScript payloads that, when executed in a user's browser, could steal session cookies, redirect users to phishing sites, or even execute additional malicious commands on the victim's machine. This vulnerability particularly threatens healthcare organizations using OpenEMR, as it could enable attackers to access sensitive patient data, manipulate medical records, or disrupt critical healthcare operations. The attack surface is further expanded by the fact that healthcare workers often trust internal applications, making social engineering attacks more effective when targeting this vulnerability.
Mitigation strategies for CVE-2021-25922 require immediate implementation of input validation and output encoding measures within the OpenEMR application framework. Organizations should prioritize upgrading to patched versions of OpenEMR that address the specific input sanitization issues, while implementing proper HTML escaping mechanisms for all user-supplied data. Security controls should include the deployment of web application firewalls that can detect and block suspicious input patterns, along with regular security assessments to identify similar vulnerabilities in other application components. Additionally, comprehensive user education programs should be established to raise awareness about suspicious links and phishing attempts, while network monitoring systems should be configured to detect anomalous traffic patterns that may indicate exploitation attempts. The vulnerability also highlights the importance of following secure coding practices and adhering to security standards such as those outlined in the OWASP Top Ten, which specifically addresses the need for proper input validation and output encoding to prevent XSS attacks. Organizations should also consider implementing content security policies to add an additional layer of protection against script execution, and establish regular vulnerability scanning procedures to identify and remediate similar issues before they can be exploited by malicious actors.