CVE-2011-4587 in moodle
Summary
by MITRE
lib/moodlelib.php in Moodle 1.9.x before 1.9.15, 2.0.x before 2.0.6, and 2.1.x before 2.1.3 does not properly handle certain zero values in the password policy, which makes it easier for remote attackers to obtain access by leveraging the possible existence of user accounts that have unchangeable blank passwords.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2011-4587 affects Moodle learning management systems across multiple versions including 1.9.x before 1.9.15, 2.0.x before 2.0.6, and 2.1.x before 2.1.3. This issue resides within the lib/moodlelib.php file and represents a significant security flaw in the platform's password policy implementation. The vulnerability specifically targets how the system handles zero values in password validation mechanisms, creating a potential pathway for unauthorized access that directly impacts user account security and system integrity.
The technical flaw manifests in the improper handling of certain zero values within Moodle's password policy enforcement system. When users attempt to set passwords, the system fails to correctly validate or process zero values, particularly those representing blank passwords. This malfunction creates a condition where accounts with empty passwords may be considered valid or acceptable by the authentication system, despite the intended security policy that should prevent such configurations. The vulnerability essentially allows attackers to exploit the system's leniency in password validation, potentially bypassing normal authentication requirements.
From an operational perspective, this vulnerability significantly increases the attack surface for remote attackers who can leverage the existence of user accounts with unchangeable blank passwords. The impact extends beyond simple credential theft to include potential account takeover scenarios where attackers can gain unauthorized access to user accounts without proper authentication. This weakness undermines the fundamental security model of the learning management system and creates persistent access points that could be exploited by malicious actors. The vulnerability is particularly concerning because it affects multiple major release branches of Moodle, indicating a widespread issue that would impact numerous educational institutions and organizations relying on the platform.
The security implications of this vulnerability align with CWE-255, which addresses improper handling of credentials, and can be mapped to ATT&CK technique T1110.003 for credential access through password guessing or exploitation of weak authentication mechanisms. Organizations using affected Moodle versions face increased risk of unauthorized access to sensitive educational data, user accounts, and institutional resources. The vulnerability essentially creates a backdoor mechanism that allows attackers to bypass normal authentication procedures, making it a critical concern for security administrators responsible for protecting educational platforms.
Mitigation strategies should prioritize immediate patching of affected Moodle installations to the latest available versions that contain the necessary security fixes. System administrators must conduct comprehensive audits of user accounts to identify and disable any accounts with blank or weak passwords, implementing mandatory password policies that enforce strong authentication requirements. Additional protective measures include implementing account lockout mechanisms, monitoring authentication attempts for suspicious patterns, and establishing regular security assessments of the learning management system infrastructure. Organizations should also consider implementing multi-factor authentication as an additional layer of security, while ensuring that all user accounts undergo proper verification and password strength validation before being activated within the system.