CVE-2020-18698 in Lin-CMS-Flask
Summary
by MITRE • 08/16/2021
Improper Authentication in Lin-CMS-Flask v0.1.1 allows remote attackers to launch brute force login attempts without restriction via the 'login' function in the component 'app/api/cms/user.py'.
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Analysis
by VulDB Data Team • 08/19/2021
The vulnerability identified as CVE-2020-18698 represents a critical authentication flaw within the Lin-CMS-Flask web application framework version 0.1.1. This issue stems from inadequate session management and login validation mechanisms that fail to implement proper rate limiting or account lockout procedures. The vulnerability specifically affects the login function located in the app/api/cms/user.py component, which serves as the primary entry point for user authentication within the system. Attackers can exploit this weakness to conduct unrestricted brute force attacks against user credentials, potentially leading to unauthorized access to administrative functions and sensitive system resources. The flaw demonstrates a fundamental failure in implementing security controls that are essential for protecting web applications from credential stuffing and brute force attacks, which are among the most common attack vectors in modern cybersecurity threats.
The technical implementation of this vulnerability reveals a critical design oversight in the authentication flow where no mechanisms exist to prevent repeated login attempts from the same source. The login function lacks proper input validation, rate limiting, or account lockout functionality that would normally be expected in production-grade applications. This weakness allows attackers to systematically test multiple username and password combinations without facing any restrictions or delays that would typically be implemented to prevent automated attacks. The absence of such protections creates an environment where malicious actors can leverage automated tools to rapidly iterate through common password lists or attempt dictionary attacks against user accounts. The vulnerability directly maps to CWE-307 - Improper Restriction of Excessive Authentication Attempts, which specifically addresses the lack of proper authentication attempt controls in software systems.
The operational impact of this vulnerability extends beyond simple credential compromise, as it provides attackers with potential access to administrative interfaces and sensitive data within the Lin-CMS-Flask framework. Successful exploitation could enable attackers to modify or delete content, access restricted administrative functions, and potentially escalate privileges within the application. The unrestricted nature of the attack means that even if individual accounts have strong passwords, the system remains vulnerable to attacks using common credential sets or password spraying techniques. This vulnerability also creates opportunities for attackers to establish persistent access patterns and could potentially be leveraged as a stepping stone for further attacks within the network infrastructure. Organizations using this framework may face significant security risks including data breaches, unauthorized modifications to content management systems, and potential compliance violations due to inadequate authentication controls.
Mitigation strategies for this vulnerability should focus on implementing robust authentication controls including rate limiting, account lockout mechanisms, and proper session management. The recommended approach involves adding proper input validation to the login function, implementing exponential backoff for failed authentication attempts, and establishing account lockout procedures after a predetermined number of failed login attempts. Organizations should also consider implementing multi-factor authentication mechanisms to add additional layers of security beyond simple username and password combinations. The solution aligns with ATT&CK technique T1110 - Brute Force, which emphasizes the importance of implementing controls to prevent credential guessing attacks. Security teams should also ensure that all authentication endpoints are properly monitored and that anomalous login patterns trigger appropriate alerts. Additionally, regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities in other components of the application. The implementation of these controls should follow established security frameworks such as NIST SP 800-63B for authentication and access management to ensure comprehensive protection against credential-based attacks.