CVE-2018-20328 in LMS
Summary
by MITRE
Chamilo LMS version 1.11.8 contains XSS in main/social/group_view.php in the social groups tool, allowing authenticated users to affect other users, under specific conditions of permissions granted by administrators. This is considered "low risk" due to the nature of the feature it exploits.
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Analysis
by VulDB Data Team • 06/20/2023
The vulnerability CVE-2018-20328 represents a cross-site scripting flaw discovered in Chamilo Learning Management System version 1.11.8 within the social groups tool functionality. This vulnerability exists in the main/social/group_view.php file and specifically targets the social groups feature that allows users to organize and interact within group environments. The flaw enables authenticated users to inject malicious scripts into group views that will execute in the contexts of other users who access these pages, creating a potential vector for various attack scenarios including session hijacking, credential theft, or redirection to malicious sites. The vulnerability requires specific permission conditions to be exploited effectively, as it depends on administrators granting certain privileges to users within the social groups framework.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output sanitization within the group view functionality. When authenticated users with appropriate permissions create or modify group content, the system fails to properly escape or filter user-supplied data before rendering it in the web interface. This allows malicious payloads to be stored and subsequently executed when other users view the affected group pages. The vulnerability is classified as a reflected XSS variant since the malicious scripts are executed from data that originates from the application's own database rather than from external sources. The attack requires a user to have access to the social groups feature and specific permissions that allow content creation or modification within group contexts, making it less trivial to exploit but still potentially dangerous in environments where users have elevated privileges.
The operational impact of this vulnerability extends beyond simple script execution as it can lead to significant security compromise within educational institutions using Chamilo LMS. An attacker with appropriate permissions could craft malicious content that would execute in the browser context of other users, potentially stealing session cookies, redirecting users to phishing sites, or performing actions on behalf of victims. The low-risk classification mentioned in the description reflects the requirement for specific administrative permissions to exploit this vulnerability effectively, but this does not diminish the potential damage that could occur in environments where privilege escalation or social engineering attacks could grant attackers access to these permissions. The vulnerability affects the integrity of user sessions and the trustworthiness of the social groups feature, potentially undermining the security posture of the entire learning management system.
Organizations should implement comprehensive input validation and output encoding mechanisms to address this vulnerability, ensuring that all user-supplied content within group views is properly sanitized before rendering. The recommended mitigation strategy includes implementing Content Security Policy headers to prevent unauthorized script execution, conducting regular security audits of user input handling mechanisms, and ensuring that administrative permissions are strictly controlled and regularly reviewed. Additionally, implementing proper privilege separation and least-privilege principles can significantly reduce the attack surface, as the vulnerability requires specific permissions to be effectively exploited. Organizations should also consider implementing web application firewalls to detect and block malicious payloads attempting to exploit this vulnerability. The fix should align with CWE-79 standards for cross-site scripting prevention and follow ATT&CK techniques related to credential access and execution through web applications, ensuring that defensive measures address both the immediate vulnerability and broader security implications within the learning management system environment.