CVE-2019-6591 in BIG-IP APM
Summary
by MITRE
On BIG-IP APM 14.0.0 to 14.0.0.4, 13.0.0 to 13.1.1.3 and 12.1.0 to 12.1.3.7, a reflected cross-site scripting (XSS) vulnerability exists in the resource information page for authenticated users when a full webtop is configured on the BIG-IP APM system.
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Analysis
by VulDB Data Team • 07/06/2023
The vulnerability described in CVE-2019-6591 represents a critical reflected cross-site scripting flaw within F5 Networks BIG-IP Access Policy Manager (APM) systems. This vulnerability affects multiple versions including 14.0.0 through 14.0.0.4, 13.0.0 through 13.1.1.3, and 12.1.0 through 12.1.3.7, making it a widespread issue across several major releases of the BIG-IP platform. The flaw specifically manifests in the resource information page functionality when a full webtop configuration is implemented on the APM system, indicating that the vulnerability is context-dependent and requires specific deployment configurations to be exploitable.
The technical nature of this vulnerability stems from improper input validation and output encoding within the webtop resource information page component of the BIG-IP APM system. When authenticated users interact with this specific page under the configured webtop environment, maliciously crafted input parameters can be reflected back to the user's browser without adequate sanitization or encoding. This creates an opportunity for attackers to inject malicious script code that executes in the context of the victim's browser session, potentially allowing for session hijacking, credential theft, or redirection to malicious sites. The vulnerability operates at the application layer and specifically targets the user interface rendering component of the access management system.
The operational impact of this vulnerability is significant for organizations relying on BIG-IP APM systems for access control and authentication. Since the vulnerability requires authentication to exploit, it primarily affects internal users who have legitimate access to the APM system, but this still represents a substantial security risk. An authenticated attacker could leverage this vulnerability to escalate their privileges within the system, access sensitive resources, or potentially use the compromised session to access other systems within the network perimeter. The reflected nature of the XSS means that the attack vector could be delivered through various means including phishing emails, compromised web links, or social engineering campaigns targeting system administrators or regular users with access permissions.
Organizations should implement immediate mitigations including applying the latest security patches provided by F5 Networks, which would address the input validation and output encoding deficiencies in the affected components. Network segmentation and monitoring should be enhanced to detect potential exploitation attempts, particularly around the webtop resource information page access patterns. Additionally, implementing proper web application firewall rules to filter suspicious input parameters and enabling security headers such as Content Security Policy can provide additional defense-in-depth measures. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws and represents a common attack pattern categorized under ATT&CK technique T1059.007 for script-based attacks. Organizations should also conduct comprehensive security assessments of their BIG-IP APM deployments to identify any other potentially vulnerable components within the system that might be susceptible to similar exploitation techniques.