CVE-2012-4238 in TCExam
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in admin/code/tce_edit_answer.php in TCExam before 11.3.008 allows remote authenticated users with level 5 or greater permissions to inject arbitrary web script or HTML via the question_subject_id parameter.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/12/2021
The vulnerability described in CVE-2012-4238 represents a critical cross-site scripting flaw within the TCExam learning management system, specifically in the administrative code component responsible for answer editing. This vulnerability affects versions prior to 11.3.008 and demonstrates a classic server-side input validation failure that enables malicious actors to execute arbitrary web scripts within the context of other users' browsers. The flaw exists in the admin/code/tce_edit_answer.php file, which processes administrative actions related to question management and answer editing. The vulnerability is particularly concerning because it requires only authentication with level 5 or greater permissions, indicating that it can be exploited by users who already possess significant administrative privileges within the system.
The technical implementation of this vulnerability stems from inadequate sanitization of the question_subject_id parameter, which is directly incorporated into the web page output without proper HTML escaping or validation. When authenticated users with sufficient privileges submit data containing malicious script code through this parameter, the system fails to properly encode or validate the input before rendering it in the browser context. This allows attackers to inject JavaScript payloads that can execute in the browsers of other users who view the affected pages. The vulnerability operates under CWE-79, which specifically addresses Cross-Site Scripting flaws in web applications, and aligns with ATT&CK technique T1566.001 for initial access through malicious web content. The attack vector requires a legitimate administrative account with level 5 or higher permissions, making it a privilege escalation concern that could be exploited by insiders or compromised administrators.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and further system compromise. An attacker who successfully exploits this vulnerability could potentially steal session cookies from other administrators, allowing them to impersonate those users and gain persistent access to the system. The vulnerability also creates opportunities for phishing attacks where malicious scripts could redirect users to fraudulent pages or steal sensitive information. Additionally, since the affected component is part of the administrative interface, successful exploitation could lead to complete system compromise, especially if the compromised administrator has access to sensitive data or system configuration controls. The presence of this vulnerability in a learning management system also raises concerns about student data protection and compliance with educational privacy regulations.
Mitigation strategies for this vulnerability should focus on immediate patching of the TCExam system to version 11.3.008 or later, where the input validation has been properly implemented. Organizations should also implement additional security measures including input validation at multiple layers, proper HTML escaping of all dynamic content, and regular security testing of web applications. The principle of least privilege should be enforced by ensuring that administrative accounts have only the minimum permissions necessary for their roles, reducing the potential impact of credential compromise. Security monitoring should include detection of unusual administrative activities and injection attempts in web application logs. Network-level protections such as web application firewalls can provide additional defense-in-depth, though they should not be considered a substitute for proper code-level fixes. Regular security awareness training for administrators can help prevent social engineering attacks that might lead to credential compromise, while incident response procedures should be established to quickly address any exploitation attempts. The vulnerability demonstrates the importance of implementing comprehensive input validation and output encoding practices as recommended in OWASP Top Ten and NIST cybersecurity guidelines for web application security.