CVE-2014-4687 in pfSense
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in pfSense before 2.1.4 allow remote attackers to inject arbitrary web script or HTML via (1) the starttime0 parameter to firewall_schedule.php, (2) the rssfeed parameter to rss.widget.php, (3) the servicestatusfilter parameter to services_status.widget.php, (4) the txtRecallBuffer parameter to exec.php, or (5) the HTTP Referer header to log.widget.php.
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Analysis
by VulDB Data Team • 03/11/2019
The vulnerability identified as CVE-2014-4687 represents a critical cross-site scripting flaw affecting pfSense versions prior to 2.1.4, demonstrating the persistent challenge of input validation in network security appliances. This vulnerability classifies under CWE-79 as it involves the injection of malicious scripts into web applications, specifically targeting the web interface of pfSense which serves as a critical component for network firewall management. The affected parameters span multiple files within the pfSense web administration interface, indicating a systemic weakness in input sanitization across different modules of the application.
The technical exploitation of this vulnerability occurs through multiple attack vectors, each targeting different components of the pfSense web interface. The starttime0 parameter in firewall_schedule.php allows attackers to inject malicious content into scheduled firewall rules, potentially compromising the integrity of network scheduling functionality. The rssfeed parameter in rss.widget.php presents an attack surface where external RSS feeds could be manipulated to deliver malicious scripts, while the servicestatusfilter parameter in services_status.widget.php could enable attackers to manipulate service status displays. The txtRecallBuffer parameter in exec.php represents a particularly dangerous vector as it could allow execution of arbitrary commands through script injection, and the HTTP Referer header in log.widget.php demonstrates how even seemingly benign headers could be weaponized for XSS attacks.
The operational impact of this vulnerability extends beyond simple script injection, as it could enable attackers to escalate privileges and potentially compromise the entire pfSense appliance. Attackers could leverage these vulnerabilities to steal session cookies, redirect users to malicious sites, or even execute commands on the underlying system, particularly when combined with the exec.php vulnerability that could allow command execution. The attack surface is particularly concerning given that pfSense appliances are often deployed in critical network infrastructure environments where such compromises could lead to complete network infiltration and unauthorized access to sensitive network traffic.
Mitigation strategies for CVE-2014-4687 should prioritize immediate patching of pfSense appliances to version 2.1.4 or later, as this represents the most effective defense against the known exploitation vectors. Organizations should implement comprehensive input validation and output encoding across all web application components, particularly focusing on parameters that receive user input from external sources. Network segmentation and access controls should be strengthened to limit exposure of the pfSense web interface to untrusted networks. The implementation of Content Security Policy headers and regular security auditing of web application components aligns with recommended practices from the ATT&CK framework for defensive measures against web-based attacks. Additionally, security monitoring should be enhanced to detect anomalous patterns in web interface access and potential exploitation attempts, ensuring that any attempts to leverage these vulnerabilities are quickly identified and mitigated.