CVE-2015-3179 in Moodle
Summary
by MITRE
login/confirm.php in Moodle through 2.5.9, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6 allows remote authenticated users to bypass intended login restrictions by leveraging access to an unconfirmed suspended account.
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Analysis
by VulDB Data Team • 05/19/2022
The vulnerability identified as CVE-2015-3179 affects Moodle learning management systems across multiple versions including 2.5.9 and earlier, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6. This security flaw exists within the login/confirm.php component and represents a critical authorization bypass issue that undermines the platform's user authentication mechanisms. The vulnerability specifically targets the system's handling of user account states, particularly when users possess suspended accounts that have not yet been confirmed.
The technical flaw stems from improper validation of account status during the login confirmation process. When authenticated users attempt to access the system with accounts that are both suspended and unconfirmed, the application fails to properly enforce the intended login restrictions. This occurs because the system does not adequately verify whether an account should be accessible despite its suspended status during the confirmation phase. The flaw allows malicious actors who have legitimate access to suspended but unconfirmed accounts to bypass the normal authentication controls that would typically prevent such access.
From an operational perspective, this vulnerability creates significant security risks for educational institutions relying on Moodle platforms. Attackers can exploit this weakness to gain unauthorized access to systems where they should be blocked due to suspended account status. The impact extends beyond simple unauthorized access as it potentially enables privilege escalation and data compromise. Organizations may experience unauthorized access to course materials, student information, and administrative functions that should remain restricted to legitimate users. This vulnerability particularly affects environments where account suspension is used as a security measure to prevent access during investigation periods or when users violate terms of service.
The vulnerability aligns with CWE-284, which addresses improper access control, and relates to ATT&CK technique T1078 for valid accounts and privilege escalation. Organizations should immediately implement mitigations including updating to the patched versions of Moodle where available, reviewing account suspension policies, and monitoring for unauthorized access attempts. Additional defensive measures include implementing stricter account validation procedures, ensuring proper account lifecycle management, and conducting regular security audits of authentication mechanisms. The remediation process should also involve verifying that all users with suspended accounts are properly restricted from accessing system resources until their accounts are fully validated and reinstated through appropriate administrative procedures.