CVE-2017-15538 in ILIAS
Summary
by MITRE
Stored XSS vulnerability in the Media Objects component of ILIAS before 5.1.21 and 5.2.x before 5.2.9 allows an authenticated user to inject JavaScript to gain administrator privileges, related to the setParameter function in Services/MediaObjects/classes/class.ilMediaItem.php.
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Analysis
by VulDB Data Team • 01/03/2023
The stored cross-site scripting vulnerability identified as CVE-2017-15538 resides within the Media Objects component of the ILIAS learning management system, affecting versions prior to 5.1.21 and 5.2.x prior to 5.2.9. This vulnerability represents a critical security flaw that enables authenticated attackers to inject malicious JavaScript code into the application's media objects functionality. The vulnerability specifically impacts the setParameter function located in Services/MediaObjects/classes/class.ilMediaItem.php, which serves as the entry point for the malicious payload injection. The flaw allows attackers to manipulate the application's behavior through persistent script injection, creating a persistent threat that can affect all users who interact with the compromised media objects.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the Media Objects component. When authenticated users submit media object parameters through the setParameter function, the application fails to properly sanitize or escape user-supplied data before storing it in the database. This stored data is then subsequently rendered without proper context-aware encoding, creating an environment where malicious JavaScript code can be executed in the context of other users' browsers. The vulnerability's classification as a stored XSS flaw means that the malicious payload is permanently stored on the server and executed whenever affected users access the compromised media objects, making it particularly dangerous for administrators who frequently interact with media content. According to CWE standards, this vulnerability maps to CWE-79, which specifically addresses Cross-site Scripting flaws, while the persistent nature of the attack aligns with CWE-80, which covers improper neutralization of script-related HTML tags.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to escalate privileges to administrator-level access within the ILIAS environment. An authenticated attacker who successfully exploits this vulnerability can craft malicious media objects that contain JavaScript code designed to hijack user sessions, steal credentials, or perform administrative actions on behalf of the victim. The attack vector is particularly concerning because it requires only authentication to the system, making it accessible to users with legitimate access who may not have administrative privileges. This vulnerability can be leveraged to create persistent backdoors within the learning management system, allowing attackers to maintain long-term access and potentially compromise the entire educational platform. The attack can be executed through the standard media object upload and parameter setting functionality, making it difficult to detect and trace.
Mitigation strategies for CVE-2017-15538 should focus on immediate patching of the affected ILIAS versions, with administrators upgrading to versions 5.1.21 or 5.2.9 and later. The fix implemented by the ILIAS development team addresses the root cause by introducing proper input validation and output sanitization mechanisms within the setParameter function. Organizations should also implement additional defensive measures including comprehensive monitoring of media object uploads, regular security scanning of uploaded content, and implementation of web application firewalls to detect and block suspicious script injection attempts. The vulnerability demonstrates the importance of input validation across all user-facing components of web applications and aligns with ATT&CK framework techniques related to command and control through web application exploitation. Security teams should also conduct thorough penetration testing of their ILIAS installations to identify any potential variants of this vulnerability that may have been previously overlooked, while implementing proper access controls and privilege separation to minimize the impact of potential exploitation.