CVE-2021-21352 in Time Tracker
Summary
by MITRE • 03/03/2021
Anuko Time Tracker is an open source, web-based time tracking application written in PHP. In TimeTracker before version 1.19.24.5415 tokens used in password reset feature in Time Tracker are based on system time and, therefore, are predictable. This opens a window for brute force attacks to guess user tokens and, once successful, change user passwords, including that of a system administrator. This vulnerability is pathced in version 1.19.24.5415 (started to use more secure tokens) with an additional improvement in 1.19.24.5416 (limited an available window for brute force token guessing).
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Analysis
by VulDB Data Team • 03/14/2021
The CVE-2021-21352 vulnerability affects Anuko Time Tracker, an open source web-based time tracking application developed in PHP. This application serves as a critical tool for organizations managing employee time tracking and project billing, making its security paramount to organizational operations. The vulnerability specifically targets the password reset functionality, which represents a fundamental security mechanism designed to allow users to regain access to their accounts when they lose their credentials. The flaw resides in how the application generates and manages reset tokens, creating a predictable security weakness that directly impacts user account integrity and system access control.
The technical flaw stems from the implementation of password reset tokens that rely on system time as their primary entropy source. This design choice fundamentally violates security best practices for generating cryptographically secure tokens, as time-based values are inherently predictable and expose the system to brute force attacks. The vulnerability is classified as a weakness in randomness generation and can be mapped to CWE-330, which addresses insufficient entropy in random number generation. Attackers can exploit this predictability by generating potential tokens within a reasonable time window, effectively bypassing the intended security measures designed to protect user accounts. The vulnerability specifically impacts the authentication and authorization processes within the application, as it allows unauthorized access to user accounts through password manipulation.
The operational impact of this vulnerability extends beyond simple account compromise, as successful exploitation enables attackers to change user passwords, including those belonging to system administrators with elevated privileges. This creates a severe escalation of privileges scenario where attackers can gain administrative control over the entire time tracking system. The vulnerability affects the confidentiality, integrity, and availability of the application's user data and system resources. Organizations relying on Anuko Time Tracker for time tracking and billing information face significant risks including unauthorized access to sensitive project data, potential financial fraud through manipulated time entries, and complete system compromise. The attack surface is particularly concerning given that the application is web-based and accessible over network connections, making it vulnerable to remote exploitation.
The vulnerability was addressed through two sequential patches released in versions 1.19.24.5415 and 1.19.24.5416. The first patch introduced more secure token generation mechanisms, moving away from time-based predictability toward cryptographically secure random number generation. This improvement aligns with security recommendations in the NIST SP 800-90A standard for random number generation and addresses the core weakness identified in the original implementation. The second patch further enhanced security by limiting the time window available for brute force token guessing, implementing rate limiting, and reducing the attack surface. This remediation approach follows the principle of defense in depth, combining multiple security controls to prevent successful exploitation. Organizations should implement these patches immediately to mitigate the risk of account compromise and unauthorized access to their time tracking systems. The vulnerability demonstrates the critical importance of proper entropy sources in security token generation and serves as a reminder of the need for robust cryptographic practices in web application development.