CVE-2021-3976 in kimai2
Summary
by MITRE • 11/19/2021
kimai2 is vulnerable to Cross-Site Request Forgery (CSRF)
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Analysis
by VulDB Data Team • 11/25/2021
The CVE-2021-3976 vulnerability affects kimai2, an open-source time-tracking application that serves as a comprehensive solution for managing work hours and project billing. This particular flaw represents a critical security weakness that allows attackers to exploit the application's lack of proper CSRF protection mechanisms. The vulnerability stems from the application's failure to implement adequate anti-CSRF tokens or validation measures when processing sensitive user actions, creating a pathway for malicious actors to manipulate authenticated sessions and execute unauthorized operations on behalf of legitimate users.
The technical implementation of this CSRF vulnerability in kimai2 occurs when users navigate to malicious websites or click on compromised links while maintaining an active session with the application. Without proper CSRF protection mechanisms such as anti-forgery tokens, hidden form fields, or origin validation checks, the application processes requests that appear legitimate but are actually initiated by attackers. This flaw specifically impacts the application's user management, time entry modification, and administrative functions where user permissions and data integrity are paramount. The vulnerability allows attackers to perform actions such as creating new users, modifying existing time entries, changing user roles, or altering billing information without the victim's knowledge or consent.
From an operational perspective, the impact of CVE-2021-3976 extends beyond simple data manipulation to potentially compromise the entire integrity of the time-tracking system. Attackers could exploit this vulnerability to alter billing records, manipulate project timelines, or gain unauthorized access to sensitive time-tracking data that organizations rely upon for financial reporting and project management. The vulnerability particularly affects organizations that depend on kimai2 for accurate time tracking and billing, as unauthorized modifications could result in significant financial discrepancies and compliance issues. Additionally, the attack surface is broadened by the fact that many organizations use kimai2 for collaborative environments where multiple users share administrative privileges, increasing the potential impact of a successful CSRF attack.
Organizations should immediately implement mitigations including the deployment of anti-CSRF tokens for all state-changing operations within the kimai2 application, ensuring that every form submission and API request includes unique validation tokens that tie to the user's session. The implementation should follow established security standards such as those outlined in CWE-352, which specifically addresses Cross-Site Request Forgery vulnerabilities. Security teams should also consider implementing Content Security Policy (CSP) headers and Origin validation checks to further strengthen the application's defenses against cross-site attacks. Additionally, regular security assessments and penetration testing should be conducted to identify any additional CSRF vulnerabilities that may exist within the application's codebase. The recommended remediation approach aligns with ATT&CK framework technique T1566, which emphasizes the importance of implementing proper validation controls to prevent unauthorized actions in web applications. Organizations should also review their application's session management mechanisms and ensure that all sensitive operations require explicit user confirmation before execution.