CVE-2014-4691 in pfSense
Summary
by MITRE
Session fixation vulnerability in pfSense before 2.1.4 allows remote attackers to hijack web sessions via a firewall login cookie.
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Analysis
by VulDB Data Team • 03/24/2022
The CVE-2014-4691 vulnerability represents a critical session fixation flaw in pfSense versions prior to 2.1.4, exposing web-based firewall management interfaces to remote exploitation. This vulnerability specifically targets the authentication mechanism of the pfSense web interface, which is widely used for network security management in enterprise and small business environments. The flaw enables attackers to manipulate session cookies during the authentication process, potentially allowing unauthorized access to firewall management functions. The vulnerability stems from the system's failure to properly regenerate session identifiers upon successful authentication, creating a persistent session token that remains unchanged throughout the authentication lifecycle.
The technical implementation of this vulnerability involves the manipulation of web session cookies during the login process. When users authenticate to the pfSense web interface, the system should generate a new, unique session identifier to prevent session hijacking attacks. However, in affected versions, the system fails to invalidate the original session token and replace it with a new one, allowing attackers who can observe or predict the initial session cookie to maintain access to the authenticated session. This behavior directly violates fundamental web security principles and creates an environment where session tokens can be reused by unauthorized parties. The vulnerability is classified under CWE-384 as a Session Fixation issue, which is categorized as a high-risk vulnerability in the CWE top 25 most dangerous software weaknesses.
The operational impact of CVE-2014-4691 extends beyond simple unauthorized access, as it provides attackers with complete administrative control over the affected firewall systems. Network administrators who rely on pfSense for their security infrastructure face significant risks including unauthorized network modifications, traffic interception, and complete bypass of firewall rules. The vulnerability is particularly concerning because pfSense is commonly deployed in environments where it serves as the primary network security gateway, making successful exploitation equivalent to gaining control over the entire network perimeter. Attackers can leverage this vulnerability to modify firewall rules, create backdoors, monitor network traffic, and potentially escalate privileges to gain deeper system access. The attack vector requires only remote access to the web interface, making it particularly dangerous for systems with exposed management ports.
Mitigation strategies for CVE-2014-4691 focus on immediate system updates and configuration hardening measures. The primary remediation involves upgrading pfSense installations to version 2.1.4 or later, where the session management has been properly addressed. Organizations should also implement network segmentation to limit access to pfSense management interfaces, ensuring that only authorized administrative workstations can reach the web interface. Additional protective measures include implementing strong authentication mechanisms such as two-factor authentication, configuring access control lists to restrict management interface access, and monitoring for suspicious login patterns. From an operational security perspective, regular security audits should be conducted to verify that session management is properly configured and that no legacy systems remain vulnerable. The vulnerability's classification under the ATT&CK framework as a credential access technique highlights the importance of implementing robust session management controls and monitoring for anomalous authentication behaviors. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and prevent similar vulnerabilities from remaining unaddressed in their network infrastructure.