CVE-2022-37162 in Claroline
Summary
by MITRE • 08/25/2022
Claroline 13.5.7 and prior is vulnerable to Cross Site Scripting (XSS). An attacker can obtain javascript code execution by adding arbitrary javascript code in the 'Location' field of a calendar event.
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Analysis
by VulDB Data Team • 10/01/2022
Claroline version 13.5.7 and earlier contains a critical cross site scripting vulnerability that allows attackers to execute arbitrary javascript code through the calendar event location field. This vulnerability represents a significant security risk as it enables persistent code injection attacks that can compromise user sessions and potentially escalate privileges within the application environment. The vulnerability exists due to insufficient input validation and output sanitization mechanisms within the calendar event creation functionality.
The technical flaw manifests when users create calendar events and input malicious javascript code into the Location field without proper sanitization. When other users view these calendar events, the malicious script executes in their browser context, potentially stealing session cookies, redirecting to malicious sites, or performing actions on behalf of authenticated users. This type of vulnerability falls under CWE-79 which specifically addresses cross site scripting flaws in web applications. The vulnerability enables attackers to bypass normal authentication mechanisms and exploit the trust relationship between users and the application.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with persistent access to user sessions and potentially the ability to perform privilege escalation attacks. An attacker could craft malicious calendar events that, when viewed by administrators or other users, would execute malicious code and potentially lead to complete system compromise. This vulnerability is particularly dangerous in educational environments where Claroline is commonly deployed, as it could allow attackers to access sensitive student data, course materials, or administrative functions. The attack vector aligns with ATT&CK technique T1566 which covers social engineering through malicious content delivery.
Mitigation strategies should include immediate input validation and output encoding for all user-supplied data within calendar event fields. Implementing Content Security Policy headers can help prevent script execution even if XSS occurs. Regular security updates and patches should be applied immediately upon availability. Input sanitization should be implemented at multiple layers including client-side validation and server-side filtering. Organizations should also consider implementing web application firewalls and monitoring for suspicious calendar event creation patterns. The vulnerability demonstrates the critical importance of proper input validation in web applications and aligns with security best practices outlined in OWASP Top Ten Project recommendations for preventing XSS attacks through proper sanitization and encoding of user inputs.