CVE-2009-2119 in Rising
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the login interface (my.logon.php3) in F5 FirePass SSL VPN 5.5 through 5.5.2 and 6.0 through 6.0.3 allows remote attackers to inject arbitrary web script or HTML via a base64-encoded xcho parameter.
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Analysis
by VulDB Data Team • 12/08/2017
The CVE-2009-2119 vulnerability represents a critical cross-site scripting flaw discovered in F5 FirePass SSL VPN appliances, specifically affecting versions 5.5 through 5.5.2 and 6.0 through 6.0.3. This vulnerability exists within the login interface component known as my.logon.php3, which serves as the primary authentication point for users accessing the secure virtual private network. The flaw stems from inadequate input validation and sanitization of user-supplied data, particularly when processing base64-encoded parameters. Attackers can exploit this weakness by crafting malicious payloads that leverage the xcho parameter, which is processed without proper security controls, thereby allowing arbitrary web script or HTML code execution within the context of authenticated sessions. This vulnerability specifically targets the authentication mechanism of the SSL VPN solution, making it particularly dangerous as it can potentially compromise user credentials and session tokens.
The technical exploitation of this vulnerability follows a classic XSS attack pattern where the base64-encoded xcho parameter is manipulated to inject malicious scripts that execute in the victim's browser when the login page is accessed. The vulnerability classification aligns with CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly sanitize user input before incorporating it into web page content. This weakness enables attackers to perform session hijacking, credential theft, and potentially establish persistent backdoors within the network infrastructure. The attack vector operates through a remote, unauthenticated access point, making it particularly attractive to threat actors seeking to compromise enterprise networks. The vulnerability demonstrates poor input validation practices and inadequate output encoding mechanisms that are fundamental security principles in web application development.
The operational impact of CVE-2009-2119 extends beyond simple script injection, as it can facilitate complete compromise of the SSL VPN infrastructure. When successfully exploited, attackers can steal session cookies, capture user credentials, and potentially escalate privileges within the network. The vulnerability affects the core authentication functionality, meaning that any user attempting to log into the FirePass system could be exposed to malicious code execution. This creates a significant risk for organizations relying on SSL VPN solutions for remote access, as the attack can occur during the authentication process itself. The exposure of user credentials through this vulnerability directly impacts the confidentiality and integrity of the network, potentially allowing attackers to gain unauthorized access to internal resources and systems. The attack can be particularly devastating in enterprise environments where SSL VPN is used for privileged access to critical infrastructure components.
Organizations should implement immediate mitigations including applying the vendor-provided security patches released by F5 for affected versions of the FirePass SSL VPN appliance. The remediation process should involve comprehensive network scanning to identify all affected systems and ensure proper patch deployment across all instances. Network segmentation and monitoring should be enhanced to detect anomalous traffic patterns that might indicate exploitation attempts. Additionally, implementing proper input validation and output encoding mechanisms at the application level can prevent similar vulnerabilities from occurring in other components of the system. Security teams should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar weaknesses in other network components, particularly those handling user input in authentication interfaces. The vulnerability serves as a reminder of the critical importance of secure coding practices and proper input sanitization in network security infrastructure components, aligning with ATT&CK technique T1190 - Exploit Public-Facing Application, which emphasizes the need for proper application hardening and input validation controls.