CVE-2012-0794 in moodle
Summary
by MITRE
The rc4encrypt function in lib/moodlelib.php in Moodle 1.9.x before 1.9.16, 2.0.x before 2.0.7, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 uses a hardcoded password of nfgjeingjk, which makes it easier for remote attackers to defeat cryptographic protection mechanisms by reading this script s source code within the open-source software distribution.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2012-0794 represents a critical cryptographic weakness in the Moodle learning management system that affects multiple version branches including 1.9.x through 2.2.x. This issue stems from a hardcoded password implementation within the rc4encrypt function located in the lib/moodlelib.php file, creating a fundamental flaw that undermines the security of the entire platform. The hardcoded password value of nfgjeingjk serves as a predictable cryptographic key that significantly weakens the encryption mechanism and exposes the system to potential exploitation.
The technical flaw manifests through the use of a static, hardcoded password within the encryption function rather than implementing proper cryptographic key management practices. This approach violates fundamental security principles and creates a predictable encryption scheme that can be easily compromised when attackers obtain access to the source code. The vulnerability directly impacts the confidentiality and integrity of data transmitted through the Moodle platform, as the RC4 encryption algorithm becomes trivially breakable when the key is known. This weakness falls under CWE-327, which addresses the use of weak cryptographic algorithms, and specifically relates to CWE-326, which covers insufficient key size or weak key generation mechanisms.
The operational impact of this vulnerability extends beyond simple data exposure, as it enables remote attackers to bypass cryptographic protection mechanisms entirely. When attackers can access the source code of the open-source distribution, they gain immediate access to the hardcoded password and can decrypt any data that was encrypted using this flawed implementation. This creates a significant risk for user authentication data, personal information, and sensitive communications within the Moodle environment. The vulnerability enables techniques categorized under ATT&CK tactic T1552, specifically targeting unsecured credentials and weak encryption methods to access sensitive data.
The security implications of this vulnerability are particularly severe given that Moodle is widely deployed in educational institutions and organizations handling sensitive user data. The hardcoded nature of the password means that once an attacker gains access to the source code, they can immediately exploit this weakness without requiring additional computational resources or time. This vulnerability essentially provides a backdoor that undermines the cryptographic security model of the entire system, making it easier for attackers to perform man-in-the-middle attacks, decrypt intercepted communications, or access user sessions and personal information. Organizations using affected Moodle versions face significant risk of data breaches and unauthorized access to their educational platforms.
Mitigation strategies for this vulnerability require immediate patching of affected Moodle installations to the latest stable versions that contain the corrected encryption implementation. System administrators should ensure that all Moodle instances are updated to versions 1.9.16, 2.0.7, 2.1.4, or 2.2.1 respectively, as these releases contain the proper cryptographic key management. Additionally, organizations should implement monitoring for unauthorized access to source code repositories and ensure that proper access controls are maintained on Moodle installations. The fix addresses the root cause by implementing proper cryptographic key generation and management practices rather than relying on hardcoded values, thereby restoring the intended security protections within the platform.