CVE-2022-42247 in pfSense
Summary
by MITRE • 10/03/2022
pfSense v2.5.2 was discovered to contain a cross-site scripting (XSS) vulnerability in the browser.php component. This vulnerability allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into a file name.
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Analysis
by VulDB Data Team • 10/29/2022
The cross-site scripting vulnerability identified as CVE-2022-42247 affects pfSense version 2.5.2 and resides within the browser.php component of the web interface. This vulnerability represents a critical security flaw that enables malicious actors to inject arbitrary web scripts or HTML content into the application's user interface. The flaw specifically manifests when the application processes file names that contain crafted payloads, allowing attackers to manipulate the browser.php component to execute unintended code within the context of a victim's browser session.
The technical exploitation of this vulnerability follows the standard XSS attack pattern where an attacker crafts a malicious payload containing script code that gets executed when a user views a specially crafted file name. The browser.php component fails to properly sanitize or encode user-supplied input, particularly file names, creating an opening for script injection attacks. This weakness enables attackers to execute malicious JavaScript code in the victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious websites. The vulnerability's impact is amplified because pfSense is a widely deployed network security platform that typically requires administrative access, making successful exploitation particularly dangerous for network infrastructure security.
The operational implications of this vulnerability extend beyond simple script execution as it compromises the integrity of the pfSense web interface and potentially the entire network security posture. Attackers could leverage this vulnerability to establish persistent access to the firewall management interface, manipulate security policies, or redirect traffic through malicious proxies. The attack surface is particularly concerning given that pfSense administrators frequently interact with the web interface to manage network security configurations, making them prime targets for session hijacking attacks that could lead to complete network compromise. This vulnerability directly aligns with CWE-79, which describes cross-site scripting flaws, and maps to attack techniques in the MITRE ATT&CK framework under T1059.007 for command and scripting interpreter and T1566 for phishing with malicious attachments.
Mitigation strategies for CVE-2022-42247 require immediate action including updating to pfSense version 2.5.3 or later where the vulnerability has been patched. Organizations should also implement additional protective measures such as web application firewalls that can detect and block XSS payloads, input validation controls that sanitize file names, and network monitoring solutions that can identify suspicious script execution patterns. Security teams should conduct thorough review of existing browser.php component usage patterns and implement proper output encoding for all user-supplied content. Network administrators should also consider implementing additional authentication controls and session management policies to limit the impact of potential successful exploitation attempts. Regular security assessments and vulnerability scanning should be performed to identify similar weaknesses in other components of the pfSense platform and ensure comprehensive protection against similar cross-site scripting vulnerabilities.