CVE-2017-6483 in ATutor
Summary
by MITRE
Multiple Cross-Site Scripting (XSS) issues were discovered in ATutor 2.2.2. The vulnerabilities exist due to insufficient filtration of user-supplied data passed to several pages (lang_code in themes/*/admin/system_preferences/language_edit.tmpl.php). An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/02/2019
The vulnerability identified as CVE-2017-6483 represents a critical cross-site scripting flaw within ATutor version 2.2.2, a widely used open-source learning management system. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly filter user-supplied data before processing. The specific issue manifests in the language editing functionality where the lang_code parameter within themes/*/admin/system_preferences/language_edit.tmpl.php remains unfiltered, creating an exploitable entry point for malicious actors. The vulnerability classification aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities resulting from insufficient input validation and output encoding. Attackers can leverage this weakness by injecting malicious scripts through the vulnerable parameter, which then executes in the context of legitimate users' browsers, potentially compromising user sessions and data integrity.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to manipulate the application's behavior and potentially escalate privileges within the ATutor environment. When an attacker successfully exploits this XSS vulnerability, they can execute arbitrary HTML and JavaScript code that persists in the victim's browser session, allowing for session hijacking, credential theft, or redirection to malicious sites. The attack surface is particularly concerning given that ATutor is used in educational institutions and organizations where users may have elevated privileges, making the potential for privilege escalation and data exfiltration significantly higher. The vulnerability affects the administrative interface of the application, which increases the risk of unauthorized access to sensitive system configurations and user data management functions.
Mitigation strategies for CVE-2017-6483 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the ATutor codebase. Organizations should immediately upgrade to a patched version of ATutor that addresses this vulnerability, as the vendor has released updates to resolve the insufficient filtration issues. Additionally, implementing proper parameter validation for the lang_code variable and other user-supplied inputs within the affected PHP template files is essential. Security measures should include the implementation of Content Security Policy (CSP) headers to limit script execution, proper HTML encoding of all dynamic content, and regular security audits of input handling mechanisms. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter and T1566 for credential access, highlighting the potential for attackers to use such vulnerabilities as initial access points for more sophisticated attacks. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability pattern.