CVE-2020-5915 in BIG-IP
Summary
by MITRE
In BIG-IP versions 15.1.0-15.1.0.4, 15.0.0-15.0.1.3, 14.1.0-14.1.2.3, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, an undisclosed TMUI page contains a vulnerability which allows a stored XSS when BIG-IP systems are setup in a device trust.
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Analysis
by VulDB Data Team • 08/26/2020
The vulnerability identified as CVE-2020-5915 affects F5 BIG-IP load balancer systems across multiple version ranges including 15.1.0 through 15.1.0.4, 15.0.0 through 15.0.1.3, 14.1.0 through 14.1.2.3, 13.1.0 through 13.1.3.3, 12.1.0 through 12.1.5.1, and 11.6.1 through 11.6.5.1. This issue resides within the TMUI (Traffic Management User Interface) component of the BIG-IP system and represents a stored cross-site scripting vulnerability that specifically manifests when BIG-IP systems are configured in device trust relationships. The vulnerability stems from improper input validation and output encoding within the TMUI page that handles device trust configurations, creating an attack surface where malicious input can be persistently stored and later executed in the context of other users' browsers.
The technical flaw manifests through a stored XSS vulnerability that leverages the TMUI interface's handling of device trust configurations. When administrators configure device trust relationships, the system processes and stores certain input parameters without adequate sanitization or encoding, allowing malicious payloads to be stored within the system's configuration data. This stored data becomes executable when other users access the affected TMUI pages, particularly those related to device trust management. The vulnerability is classified as CWE-79 - Cross-site Scripting and operates under the ATT&CK framework as part of the T1059.001 technique for Command and Scripting Interpreter, specifically targeting web application interfaces. The attack requires a user with administrative privileges to interact with the device trust configuration pages, making it particularly dangerous in environments where administrative access is not properly segmented.
The operational impact of this vulnerability extends beyond simple browser-based attacks as it can enable attackers to escalate privileges and gain unauthorized access to sensitive system information. When exploited, the stored XSS can allow attackers to execute malicious JavaScript code in the context of authenticated users' browsers, potentially leading to session hijacking, data exfiltration, or further system compromise. In device trust scenarios, where multiple BIG-IP systems are configured to trust each other, the vulnerability could enable attackers to compromise entire clusters of load balancers simultaneously. The stored nature of the vulnerability means that even after the initial exploitation, the malicious code continues to execute whenever affected pages are accessed, making detection and remediation more challenging. This vulnerability directly impacts the integrity and confidentiality of the BIG-IP system's administrative interface, potentially exposing sensitive configuration data and system credentials.
Mitigation strategies for CVE-2020-5915 should prioritize immediate patching of affected systems with the latest F5 security updates, which address the input validation and output encoding flaws in the TMUI component. Organizations should implement network segmentation to limit access to device trust configuration pages to only authorized administrators, reducing the attack surface. Additionally, monitoring for suspicious activity in device trust configurations and implementing web application firewalls can help detect and prevent exploitation attempts. The vulnerability's classification as CWE-79 emphasizes the need for robust input validation and output encoding practices, while its relationship to ATT&CK T1059.001 highlights the importance of protecting administrative interfaces from unauthorized access. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the BIG-IP system, ensuring comprehensive protection against similar stored XSS vulnerabilities.