CVE-2019-14830 in Moodle
Summary
by MITRE • 03/20/2021
A vulnerability was found in Moodle 3.7 to 3.7.1, 3.6 to 3.6.5, 3.5 to 3.5.7 and earlier unsupported versions, where the mobile launch endpoint contained an open redirect in some circumstances, which could result in a user's mobile access token being exposed. (Note: This does not affect sites with a forced URL scheme configured, mobile service disabled, or where the mobile app login method is "via the app").
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Analysis
by VulDB Data Team • 04/03/2021
This vulnerability exists within the Moodle learning management system and represents a critical security flaw in the mobile application integration component. The issue manifests in versions ranging from 3.5.0 through 3.7.1, affecting organizations that utilize the mobile launch endpoint functionality. The vulnerability is classified as an open redirect vulnerability, which occurs when an application redirects users to external URLs without proper validation of the destination. This particular flaw specifically impacts the mobile access token handling process during authentication sequences, creating potential exposure points for sensitive authentication credentials.
The technical implementation of this vulnerability stems from insufficient input validation within the mobile launch endpoint. When users access Moodle through mobile applications, the system generates access tokens that are essential for maintaining secure session states. The flaw allows malicious actors to manipulate the redirect parameters to point to attacker-controlled domains, potentially capturing these access tokens during the authentication flow. This type of vulnerability falls under CWE-601 which specifically addresses open redirect vulnerabilities where applications fail to validate redirect destinations. The attack vector typically involves crafting malicious URLs that appear legitimate to users while redirecting them to attacker-controlled endpoints that can capture the mobile access tokens.
The operational impact of this vulnerability extends beyond simple credential exposure, as it can enable unauthorized access to Moodle environments and potentially facilitate further attacks within the educational institution's network. Mobile access tokens are particularly sensitive because they often provide access to restricted course materials, gradebooks, and administrative functions that users might not normally have access to through standard web browsing. This vulnerability is especially concerning in educational environments where Moodle systems contain sensitive student data, personal information, and academic records. The exposure of these tokens could allow attackers to impersonate legitimate users and gain persistent access to the learning management system. According to ATT&CK framework, this vulnerability maps to T1566 which covers phishing techniques and T1078 which covers valid accounts as the attacker can leverage the stolen tokens to maintain access to the system without detection.
Organizations should immediately implement several mitigation strategies to address this vulnerability. The primary recommendation is to upgrade to the patched versions of Moodle where available, specifically versions 3.5.8, 3.6.6, and 3.7.2 or higher. For environments where immediate upgrades are not feasible, administrators should consider disabling the mobile service entirely if it is not required for operations. The configuration settings should also be reviewed to ensure that forced URL schemes are properly implemented, as this prevents the vulnerability from being exploited. Additionally, network monitoring should be enhanced to detect suspicious redirect patterns and token leakage attempts. Security teams should also implement proper access controls and regularly audit mobile application access logs to identify potential unauthorized access attempts. Organizations should also consider implementing additional security measures such as token rotation policies and enhanced authentication mechanisms to reduce the potential impact of any successful exploitation attempts.