CVE-2023-49829 in Tutor LMS Plugin
Summary
by MITRE • 12/15/2023
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Themeum Tutor LMS – eLearning and online course solution allows Stored XSS.This issue affects Tutor LMS – eLearning and online course solution: from n/a through 2.2.4.
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Analysis
by VulDB Data Team • 01/11/2024
The CVE-2023-49829 vulnerability represents a critical cross-site scripting flaw within the Themeum Tutor LMS platform that enables stored XSS attacks. This vulnerability exists in the web page generation process where input validation and sanitization mechanisms fail to properly neutralize malicious user inputs before they are rendered in web pages. The flaw specifically impacts the eLearning and online course solution software, with affected versions ranging from the initial release through version 2.2.4. The vulnerability allows attackers to inject malicious scripts that persist in the application's database and execute whenever affected pages are loaded by other users, creating a persistent threat vector that can compromise multiple users within the system.
The technical implementation of this vulnerability stems from inadequate input filtering and output encoding practices within the Tutor LMS application. When users submit content through various interface elements such as course descriptions, user profiles, or discussion forums, the application fails to properly sanitize these inputs before storing them in the database. This stored data is then retrieved and displayed without proper HTML escaping or context-appropriate encoding, allowing malicious script payloads to execute in the browsers of unsuspecting users who view the affected content. The vulnerability is classified as a stored XSS due to the persistence of malicious code in the application's backend storage, distinguishing it from reflected XSS attacks that require specific user interaction with crafted links.
The operational impact of this vulnerability extends beyond simple script execution, creating significant risks for educational institutions and organizations relying on the Tutor LMS platform for their online learning operations. Attackers can exploit this vulnerability to steal user session cookies, redirect victims to malicious websites, inject malware delivery mechanisms, or perform actions on behalf of authenticated users. The persistent nature of stored XSS means that once an attacker successfully injects malicious code, it continues to affect all users who access the compromised content until the vulnerability is patched and the malicious data is removed from the system. This creates a prolonged attack surface that can be leveraged for credential theft, data exfiltration, or establishment of backdoor access points within the organization's learning management environment.
Organizations utilizing Tutor LMS version 2.2.4 or earlier should immediately implement mitigation strategies while planning for the necessary software updates. The primary remediation approach involves applying the vendor's official security patch or upgrade to version 2.2.5 or later, which should contain the necessary input sanitization and output encoding fixes. In addition to patching, administrators should implement input validation at multiple layers including client-side and server-side filtering, employ proper HTML escaping mechanisms for all dynamic content, and consider implementing content security policies to limit the execution of unauthorized scripts. Security monitoring should be enhanced to detect unusual content submissions, and regular security audits should verify that all user inputs are properly sanitized before database storage. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a clear violation of the principle of least privilege and proper input validation as outlined in the ATT&CK framework under the web application attack patterns category.