CVE-2011-4582 in Moodle
Summary
by MITRE
Open redirect vulnerability in the Calendar set page in Moodle 2.1.x before 2.1.3 allows remote authenticated users to redirect users to arbitrary web sites and conduct phishing attacks via a redirection URL.
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Analysis
by VulDB Data Team • 02/18/2019
The vulnerability described in CVE-2011-4582 represents a critical open redirect flaw within Moodle's calendar functionality, specifically affecting versions 2.1.x prior to 2.1.3. This issue resides in the Calendar set page where the application fails to properly validate and sanitize user-supplied redirection URLs. The vulnerability enables authenticated attackers to craft malicious URLs that, when clicked by unsuspecting users, will redirect them to arbitrary web addresses controlled by the attacker. This open redirect condition fundamentally undermines the trust model of the web application by allowing malicious actors to manipulate the intended destination of user navigation flows.
From a technical perspective, the flaw manifests as insufficient input validation in the calendar set page implementation where user-provided redirect parameters are directly processed without proper sanitization or verification against a trusted domain whitelist. The vulnerability is classified as a CWE-601 Open Redirect vulnerability under the Common Weakness Enumeration framework, specifically categorized as a web application security flaw that permits attackers to redirect users to malicious sites. The attack vector requires only authenticated access to the Moodle system, making it particularly dangerous as it can be exploited by users with legitimate access credentials who may not be authorized to perform such actions.
The operational impact of this vulnerability extends beyond simple redirection, as it provides attackers with a powerful vector for conducting sophisticated phishing campaigns and social engineering attacks. When users are redirected to attacker-controlled domains, they may be tricked into entering sensitive information such as login credentials, personal data, or financial details. The threat model aligns with ATT&CK technique T1566.001 for Phishing, where the open redirect serves as an initial access vector to deliver malicious payloads or harvest credentials from unsuspecting users within the Moodle environment. This vulnerability is particularly concerning in educational institutions where Moodle systems typically contain sensitive user data, course materials, and personal information.
Organizations affected by this vulnerability should immediately implement the patch released with Moodle version 2.1.3, which addresses the input validation issue by properly sanitizing redirect URLs and implementing domain validation checks. Additional mitigations include implementing web application firewalls with URL validation rules, configuring proper access controls to limit user privileges, and conducting security awareness training for users to recognize suspicious redirection attempts. The vulnerability demonstrates the critical importance of input validation in web applications and serves as a reminder of the potential for authenticated users to be leveraged as attack vectors within enterprise environments. Security teams should also consider implementing monitoring solutions to detect unusual redirection patterns and establish incident response procedures for handling such security events.