CVE-2018-11565 in Mahara
Summary
by MITRE
Mahara 17.04 before 17.04.8 and 17.10 before 17.10.5 and 18.04 before 18.04.1 are vulnerable to mentioning the usernames that are already taken by people registered in the system rather than masking that information.
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Analysis
by VulDB Data Team • 02/10/2020
This vulnerability exists in the Mahara learning management system where the application fails to properly handle user registration requests by revealing whether a username is already taken. The flaw affects versions prior to specific patches including 17.04.8, 17.10.5, and 18.04.1, creating an information disclosure risk that can be exploited by malicious actors. The vulnerability stems from the application's inadequate validation and response handling during the user registration process, where it provides explicit feedback about existing usernames instead of implementing generic responses that would mask this information.
The technical implementation of this vulnerability allows attackers to perform user enumeration attacks by systematically testing usernames against the registration endpoint. When a user attempts to register with an already existing username, the system returns a specific error message indicating that the username is taken rather than providing a generic failure response. This behavior directly violates security best practices for authentication and user management systems, as it exposes the existence of valid user accounts within the system. The vulnerability can be classified under CWE-200 as "Information Exposure" and specifically relates to CWE-384, which addresses the exposure of sensitive information through improper error handling.
The operational impact of this vulnerability is significant as it enables attackers to gather intelligence about the user base of the Mahara system. Security researchers and malicious actors can leverage this information to conduct targeted attacks such as credential stuffing, social engineering campaigns, or brute force attempts against known usernames. The exposure of existing usernames provides attackers with valuable reconnaissance data that can be used to compromise accounts through password reuse or targeted phishing attacks. This vulnerability essentially undermines the principle of least privilege and proper access control by making user account information readily available to unauthorized parties.
Organizations using affected versions of Mahara should immediately apply the security patches released by the vendor to address this vulnerability. The mitigation strategy involves implementing proper input validation and error handling mechanisms that provide generic responses regardless of whether a username exists in the system. Security teams should also consider implementing additional protections such as account lockout mechanisms, rate limiting on registration attempts, and monitoring for unusual registration patterns that may indicate automated enumeration attempts. From an ATT&CK framework perspective, this vulnerability maps to T1078 "Valid Accounts" and T1566 "Phishing" as it enables adversaries to gather valid account information for subsequent exploitation phases. The implementation of proper security controls should include regular security assessments, input sanitization, and adherence to secure coding practices that prevent information disclosure through error messages and system responses.