CVE-2006-4943 in Moodle
Summary
by MITRE
course/jumpto.php in Moodle before 1.6.2 does not validate the session key (sesskey) before providing content from arbitrary local URIs, which allows remote attackers to obtain sensitive information via the jump parameter.
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Analysis
by VulDB Data Team • 08/04/2018
The vulnerability described in CVE-2006-4943 affects Moodle versions prior to 1.6.2 and resides in the course/jumpto.php script. This flaw represents a critical security oversight that undermines the integrity of session management within the learning management system. The vulnerability specifically targets the absence of proper session key validation mechanisms, creating an exploitable condition that allows remote attackers to manipulate the jump parameter and access arbitrary local URIs. This issue fundamentally compromises the authentication and authorization controls that should protect sensitive system resources and user data.
The technical implementation of this vulnerability stems from insufficient input validation within the jumpto.php script. When users navigate through course content using the jump functionality, the system should verify that the sesskey parameter matches the current session before processing any URI requests. However, in affected versions, this validation step is completely omitted or inadequately implemented. Attackers can exploit this by crafting malicious requests that include crafted jump parameters pointing to local system paths or sensitive files. The absence of proper sesskey validation means that any authenticated user can potentially bypass normal access controls and retrieve content that should otherwise be restricted. This vulnerability aligns with CWE-601 which addresses URL redirector abuse and represents a classic case of insecure direct object reference where the system fails to validate user-provided input against legitimate session contexts.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential system compromise and data exfiltration. An attacker who successfully exploits this vulnerability could access sensitive files such as configuration settings, user databases, system logs, or other confidential information stored on the server. The remote nature of the attack means that exploitation does not require physical access to the system, making it particularly dangerous for organizations running vulnerable Moodle installations. The vulnerability affects the core authentication mechanisms of the platform, potentially allowing unauthorized access to course materials, user information, and administrative functions. This type of vulnerability can serve as a stepping stone for more sophisticated attacks, as it provides attackers with initial access to internal system resources that could be used to escalate privileges or conduct further reconnaissance.
The exploitation of this vulnerability demonstrates a clear violation of security principles and represents a failure in the principle of least privilege. According to ATT&CK framework, this vulnerability maps to techniques involving privilege escalation and information gathering through insecure direct object references. Organizations running affected Moodle versions face significant risk of data breaches, compliance violations, and reputational damage. The vulnerability also highlights the importance of proper input validation and session management in web applications, as outlined in security standards such as OWASP Top Ten. System administrators should immediately implement the available patches and updates to address this vulnerability, while also conducting thorough security assessments to identify any potential exploitation attempts. Additional mitigations should include network segmentation, monitoring for suspicious URI access patterns, and implementing proper access controls to limit the impact of potential exploitation attempts.
This vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and implementing comprehensive security testing procedures. The lack of sesskey validation in the jumpto.php script represents a fundamental flaw in the application's security architecture that could have been prevented through proper code review and security testing. Organizations should establish robust patch management processes and regularly audit their web applications for similar vulnerabilities. The incident underscores the necessity of following security best practices such as input validation, proper session management, and implementing defense-in-depth strategies to protect against such exploitation techniques.