CVE-2015-7712 in ATutor
Summary
by MITRE
Multiple eval injection vulnerabilities in mods/_standard/gradebook/edit_marks.php in ATutor 2.2 and earlier allow remote authenticated users with the AT_PRIV_GRADEBOOK privilege to execute arbitrary PHP code via the (1) asc or (2) desc parameter.
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Analysis
by VulDB Data Team • 06/27/2022
The CVE-2015-7712 vulnerability represents a critical server-side code injection flaw within the ATutor learning management system version 2.2 and earlier. This vulnerability exists in the mods/_standard/gradebook/edit_marks.php file and specifically targets the handling of user-supplied input through the asc and desc parameters. The flaw allows authenticated users with the AT_PRIV_GRADEBOOK privilege to execute arbitrary PHP code remotely, fundamentally compromising the system's integrity and security posture.
The technical implementation of this vulnerability stems from improper input validation and sanitization within the gradebook editing functionality. When users with appropriate privileges submit requests containing malicious payloads in the asc or desc parameters, the application fails to properly sanitize these inputs before processing them within eval() function calls. This creates a classic server-side request forgery scenario where user-controllable data is directly interpreted as executable code. The vulnerability aligns with CWE-94, which defines weaknesses related to the execution of unintended code, specifically covering improper use of eval() functions with untrusted input. The attack vector requires authentication and specific privilege levels, making it less broadly exploitable but still highly dangerous within the context of the application's user permissions model.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and data breaches. An attacker with the AT_PRIV_GRADEBOOK privilege can manipulate gradebook data, execute arbitrary commands on the server, potentially escalate privileges to system administrators, and access sensitive educational data including student records and academic performance metrics. This vulnerability directly violates the principle of least privilege and undermines the trust model of the LMS environment. The implications are particularly severe in educational institutions where ATutor is deployed, as the compromised system could lead to academic dishonesty, data leakage, and regulatory compliance violations under various privacy frameworks including FERPA and GDPR.
Mitigation strategies for CVE-2015-7712 must address both immediate remediation and long-term security architecture improvements. The primary fix involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in dynamic code execution contexts. The eval() function calls should be eliminated or replaced with safer alternatives such as array lookups or switch statements. Additionally, the application should enforce strict parameter validation for asc and desc values, ensuring they only accept predefined safe values. This vulnerability demonstrates the importance of following secure coding practices outlined in OWASP Top 10 and the MITRE ATT&CK framework, specifically addressing techniques related to code injection and privilege escalation. Organizations should also implement comprehensive monitoring and logging of gradebook modifications to detect anomalous activities and maintain audit trails for compliance purposes. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the application and prevent similar injection attacks from compromising the system's overall security posture.