CVE-2018-11678 in Monstra
Summary
by MITRE
plugins/box/users/users.plugin.php in Monstra CMS 3.0.4 allows Login Rate Limiting Bypass via manipulation of the login_attempts cookie.
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Analysis
by VulDB Data Team • 02/15/2020
The vulnerability identified as CVE-2018-11678 resides within the Monstra CMS 3.0.4 content management system, specifically in the user authentication plugin located at plugins/box/users/users.plugin.php. This flaw represents a critical security weakness that directly impacts the system's ability to enforce login rate limiting mechanisms, potentially allowing malicious actors to bypass protective measures designed to prevent brute force attacks. The vulnerability stems from improper handling of the login_attempts cookie, which is typically used to track failed login attempts and implement temporary account lockouts or delays. When this cookie is manipulated by an attacker, the system fails to properly validate the authentication attempts, effectively nullifying the rate limiting controls that should be in place to protect user accounts from automated attack vectors.
The technical implementation of this vulnerability allows attackers to manipulate the login_attempts cookie value in ways that circumvent the intended security controls. This manipulation enables unauthorized users to perform unlimited login attempts without triggering the protective rate limiting mechanisms that would normally be activated after a predetermined number of failed attempts. The flaw operates at the application layer, specifically targeting the authentication logic that should enforce time-based delays or account lockouts following multiple unsuccessful login attempts. This bypass mechanism directly violates standard security practices for authentication systems and represents a failure in input validation and session management controls. The vulnerability can be classified under CWE-305 Authentication Bypass Through User Identification Error, as it allows attackers to circumvent the intended authentication flow through cookie manipulation.
From an operational impact perspective, this vulnerability creates significant risk for Monstra CMS installations, as it provides attackers with an effective means to conduct brute force attacks against user accounts without facing the normal protective measures that would typically slow or prevent such attempts. The bypass allows for rapid successive login attempts that could lead to account compromise through credential stuffing or password spraying techniques. Security teams would find it extremely difficult to detect these attacks through normal monitoring since the system appears to be functioning normally while simultaneously allowing unauthorized access attempts to proceed unchecked. The vulnerability essentially renders the rate limiting protection mechanism ineffective, potentially allowing attackers to gain unauthorized access to user accounts, administrative panels, or sensitive data within the CMS environment. This weakness particularly affects systems where user authentication is critical and where the CMS is used to manage sensitive content or user data.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and cookie integrity checks within the authentication plugin. The recommended approach involves implementing server-side validation of login attempts that cannot be easily manipulated by client-side cookie modifications, including cryptographic signing or hashing of cookie values to prevent tampering. Organizations should also implement robust session management controls that track authentication attempts independently of client-side cookies and enforce rate limiting based on server-side session data rather than relying solely on cookie manipulation. Additional security measures include implementing account lockout mechanisms that are not easily bypassable through cookie manipulation, deploying intrusion detection systems to monitor for unusual login patterns, and ensuring that all authentication-related components are properly secured against tampering. The mitigation aligns with ATT&CK technique T1110.003 Credential Stuffing and T1110.001 Brute Force, as it addresses the methods used to bypass authentication protections. Security architects should also consider implementing multi-factor authentication as an additional layer of protection and ensure that all CMS components are regularly updated to address known vulnerabilities. The fix requires modifications to the users.plugin.php file to enforce server-side validation of authentication attempts and prevent client-side manipulation of rate limiting controls.