CVE-2020-5932 in BIG-IP ASM
Summary
by MITRE • 10/30/2020
On BIG-IP ASM 15.1.0-15.1.0.5, a cross-site scripting (XSS) vulnerability exists in the BIG-IP ASM Configuration utility response and blocking pages. An authenticated user with administrative privileges can specify a response page with any content, including JavaScript code that will be executed when preview is opened.
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Analysis
by VulDB Data Team • 11/30/2020
The vulnerability described in CVE-2020-5932 represents a critical cross-site scripting flaw within the BIG-IP Application Security Manager (ASM) configuration utility. This vulnerability specifically affects BIG-IP ASM versions 15.1.0 through 15.1.0.5, exposing organizations to potential malicious code execution through web interface manipulation. The issue resides in how the system handles response and blocking pages within the administrative configuration utility, creating an attack vector that leverages user privilege escalation to achieve persistent XSS exploitation.
The technical flaw stems from insufficient input validation and sanitization within the BIG-IP ASM administrative interface. When an authenticated administrator configures response pages for security policies, the system fails to properly sanitize user-supplied content, particularly JavaScript code embedded within response page parameters. This vulnerability operates under CWE-79 which specifically addresses cross-site scripting flaws, where the application does not properly validate or escape user-provided data before rendering it in web responses. The flaw allows for arbitrary code execution when preview functionality is utilized, as the system directly renders user-supplied content without adequate security controls.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it provides attackers with a pathway to compromise the entire BIG-IP management interface. An authenticated attacker with administrative privileges can craft malicious response pages that execute JavaScript code in the context of other administrators who preview these pages. This creates a persistent threat vector where attackers can establish backdoors, steal session cookies, perform unauthorized administrative actions, or exfiltrate sensitive configuration data. The vulnerability is particularly dangerous because it operates within the administrative context, meaning any successful exploitation could lead to complete system compromise and unauthorized access to all protected applications and data.
Organizations should immediately implement mitigations including applying the latest security patches released by F5, which address this specific vulnerability through enhanced input validation and sanitization. Network segmentation and privilege least-privilege principles should be enforced to limit administrative access to only essential personnel. Regular monitoring of administrative interface access logs and implementing web application firewalls can help detect and prevent exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1059.007 for 'Command and Scripting Interpreter: JavaScript' and T1548.002 for 'Abuse Elevation Control Mechanism' as it exploits administrative privileges to execute malicious code. Additional defensive measures should include implementing content security policies, disabling unnecessary administrative preview functionality, and conducting regular security assessments of the BIG-IP configuration utility to identify similar vulnerabilities in other administrative interfaces.