CVE-2012-6098 in Moodle
Summary
by MITRE
grade/edit/outcome/edit_form.php in Moodle 1.9.x through 1.9.19, 2.1.x before 2.1.10, 2.2.x before 2.2.7, 2.3.x before 2.3.4, and 2.4.x before 2.4.1 does not properly enforce the moodle/grade:manage capability requirement, which allows remote authenticated users to convert custom outcomes into standard site-wide outcomes by leveraging the teacher role and using the re-editing feature.
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Analysis
by VulDB Data Team • 02/25/2019
The vulnerability described in CVE-2012-6098 represents a significant access control flaw within the Moodle learning management system that affects multiple version branches including 1.9.x through 1.9.19, 2.1.x through 2.1.9, 2.2.x through 2.2.6, 2.3.x through 2.3.3, and 2.4.x through 2.4.0. This issue stems from improper capability enforcement in the grade management module, specifically within the grade/edit/outcome/edit_form.php file. The vulnerability allows authenticated users with the teacher role to exploit a logical flaw in the system's permission model to escalate their privileges and manipulate grade outcomes across the entire site. The core technical flaw manifests as a failure to properly validate the moodle/grade:manage capability requirement, which should restrict access to grade management functions to users with appropriate administrative permissions. This misconfiguration creates a path for privilege escalation where users can leverage their existing teacher role to perform actions that should be restricted to higher-privilege users. The vulnerability operates through the re-editing feature of the grade management system, allowing attackers to convert custom outcomes into standard site-wide outcomes, effectively bypassing the intended security boundaries that should separate teacher-level access from system-wide grade management capabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially compromise the integrity of the entire grade management system within Moodle installations. When exploited, the vulnerability allows attackers to modify grade outcomes that should be restricted to administrators or grade managers, potentially affecting the academic records and evaluation processes of multiple users across the platform. This capability can be particularly dangerous in educational environments where grade accuracy and integrity are paramount for student progression and institutional credibility. The vulnerability affects the core grade management functionality that underpins academic assessment systems, making it a critical security concern for educational institutions relying on Moodle for their learning management needs. The attack vector requires only authenticated access with teacher-level privileges, making it relatively easy to exploit within environments where teachers have legitimate access to the system but should not be able to perform system-wide grade modifications.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which describes improper access control issues in software systems, and represents a clear example of how insufficient capability validation can lead to privilege escalation attacks. The vulnerability also maps to ATT&CK technique T1078 which covers valid accounts and legitimate credentials as a means of gaining access to systems. Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant security patches, reviewing and tightening capability assignments for teacher roles, and monitoring for unauthorized grade modifications. The recommended approach involves updating to patched versions of Moodle as specified in the affected version ranges, implementing role-based access controls that strictly enforce the moodle/grade:manage capability, and conducting security audits of existing grade management configurations. Additionally, organizations should consider implementing network segmentation and monitoring solutions to detect anomalous grade modification activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper capability enforcement in web applications and highlights the need for comprehensive security testing of access control mechanisms, particularly in educational platforms where user roles and permissions can have significant operational impacts.