CVE-2020-5853 in BIG-IP APM
Summary
by MITRE
In BIG-IP APM portal access on versions 15.0.0-15.1.0, 14.0.0-14.1.2.3, 13.1.0-13.1.3.2, 12.1.0-12.1.5, and 11.5.2-11.6.5.1, when backend servers serve HTTP pages with special JavaScript code, this can lead to internal portal access name conflict.
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Analysis
by VulDB Data Team • 03/21/2024
The vulnerability described in CVE-2020-5853 represents a significant security flaw within F5 BIG-IP APM (Application Portal Manager) systems that affects multiple version ranges across different major releases. This issue specifically manifests when backend servers deliver HTTP content containing specially crafted JavaScript code that can interfere with the internal portal access mechanisms. The flaw exploits a naming conflict scenario that occurs during portal access operations, potentially allowing unauthorized access to internal resources that should remain protected. The vulnerability is particularly concerning because it affects widely deployed versions of the BIG-IP platform, making it a prevalent concern across enterprise networks that rely on F5's application delivery controllers for critical infrastructure protection. The impact extends beyond simple access control bypasses as it can potentially enable attackers to escalate privileges and gain deeper access to internal network resources that are typically isolated from external exposure.
The technical mechanism underlying this vulnerability involves the interaction between the BIG-IP APM portal access system and backend HTTP responses containing malicious JavaScript code. When such content is processed by the APM system, the special JavaScript elements can cause conflicts in how internal portal access names are resolved or handled, leading to unexpected behavior in the access control mechanisms. This type of vulnerability falls under the category of input validation and output encoding flaws, which are commonly classified as CWE-79 (Cross-site Scripting) or CWE-116 (Improper Encoding or Escaping of Output) depending on the specific implementation details. The vulnerability demonstrates a classic case of insufficient sanitization of user-supplied content that flows through the application portal system, creating opportunities for attackers to manipulate internal access controls through carefully crafted web content.
The operational impact of CVE-2020-5853 extends far beyond simple unauthorized access scenarios as it can potentially enable attackers to compromise entire internal network segments that are supposed to be protected by the BIG-IP APM infrastructure. Organizations using affected versions of the platform may experience unauthorized access to sensitive internal applications, data, and services that should only be accessible through proper authentication and authorization mechanisms. The vulnerability can be particularly dangerous in environments where the APM system serves as a gateway to critical business applications, as successful exploitation could lead to data breaches, service disruption, or lateral movement within the network. Additionally, the vulnerability may be leveraged as a stepping stone for more sophisticated attacks, as it can potentially provide attackers with access to internal network resources that could then be used to launch further attacks against other systems. This makes the vulnerability particularly attractive to threat actors who are looking to establish persistent access within enterprise networks.
Organizations affected by CVE-2020-5853 should prioritize immediate remediation through official F5 security patches and updates, as the vulnerability affects multiple supported versions of the BIG-IP platform. The recommended mitigation strategy involves upgrading to patched versions of the software, which typically include enhanced input validation and output encoding mechanisms that prevent the JavaScript code manipulation from causing portal access name conflicts. Security teams should also implement network segmentation and monitoring controls to detect potential exploitation attempts, as the vulnerability may be used in conjunction with other attack vectors. Organizations should review their current access control policies and ensure that proper network architecture is in place to limit the potential impact of such vulnerabilities. The ATT&CK framework would categorize this vulnerability under T1071.004 (Application Layer Protocol: DNS) and T1068 (Local Port) techniques, as the exploitation may involve manipulating portal access mechanisms and potentially establishing unauthorized network connections. Additionally, implementing proper input validation controls and output encoding practices can help prevent similar vulnerabilities from being exploited in the future, aligning with security best practices outlined in NIST SP 800-160 and ISO/IEC 27001 standards.