CVE-2021-31745 in Pluck-CMS
Summary
by MITRE • 12/10/2021
Session Fixation vulnerability in login.php in Pluck-CMS Pluck 4.7.15 allows an attacker to sustain unauthorized access to the platform. Because Pluck does not invalidate prior sessions after a password change, access can be sustained even after an administrator performs regular remediation attempts such as resetting their password.
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Analysis
by VulDB Data Team • 12/15/2021
The CVE-2021-31745 vulnerability represents a critical session fixation flaw within the Pluck-CMS 4.7.15 platform that fundamentally undermines authentication security mechanisms. This vulnerability specifically affects the login.php component and exploits a fundamental weakness in session management protocols that allows attackers to maintain persistent unauthorized access to the system. The flaw stems from the application's failure to properly invalidate existing sessions when users undergo authentication changes, creating a persistent access vector that persists beyond normal security remediation procedures.
From a technical perspective, the vulnerability operates through a session management failure that aligns with CWE-384, which addresses session fixation vulnerabilities in web applications. The core issue occurs when an administrator changes their password through the standard remediation process, yet the system fails to invalidate the previously established session tokens. This design flaw creates a scenario where an attacker who has already obtained valid session credentials can continue operating within the compromised system even after legitimate password resets have occurred. The vulnerability demonstrates a clear breakdown in the principle of least privilege and proper session lifecycle management.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to maintain persistent presence within the system for extended periods without detection. This persistent access capability significantly increases the potential for data exfiltration, system compromise, and lateral movement within the network. The vulnerability particularly affects administrative accounts, as these are often the most valuable targets for attackers seeking to establish long-term access to critical systems. Security professionals must recognize that this vulnerability can bypass standard security controls and remediation procedures that would normally prevent continued unauthorized access.
Mitigation strategies for CVE-2021-31745 should focus on implementing proper session invalidation mechanisms during authentication events. Organizations should ensure that all session tokens are immediately invalidated upon password changes, account lockouts, or other authentication modifications. The fix should incorporate session management best practices that align with NIST SP 800-116 guidelines for session management and security. Additionally, implementing automatic session timeout mechanisms and monitoring for unusual session behavior can help detect potential exploitation attempts. Security teams should also consider implementing multi-factor authentication as an additional layer of protection to mitigate the impact of session fixation vulnerabilities when they cannot be immediately patched.
The vulnerability demonstrates the critical importance of proper session management in web applications and highlights the need for regular security assessments of authentication mechanisms. It serves as a reminder that even seemingly minor session management flaws can create significant security risks that persist beyond normal remediation procedures. Organizations should conduct comprehensive security reviews of their session management implementations and ensure that all authentication-related changes properly invalidate existing sessions to prevent similar vulnerabilities from being exploited in their environments.