CVE-2019-6599 in BIG-IP
Summary
by MITRE
In BIG-IP 11.6.1-11.6.3.2 or 11.5.1-11.5.8, or Enterprise Manager 3.1.1, improper escaping of values in an undisclosed page of the configuration utility may result with an improper handling on the JSON response when it is injected by a malicious script via a remote cross-site scripting (XSS) attack.
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Analysis
by VulDB Data Team • 08/01/2023
The vulnerability identified as CVE-2019-6599 affects F5 BIG-IP systems running specific versions including 11.6.1 through 11.6.3.2, 11.5.1 through 11.5.8, and Enterprise Manager 3.1.1. This issue resides within the configuration utility's handling of user-supplied data, specifically in an undisclosed page that processes input values without proper sanitization. The flaw represents a critical security weakness that enables attackers to exploit cross-site scripting vulnerabilities through malicious script injection techniques. The vulnerability stems from inadequate input validation and output encoding mechanisms that fail to properly escape special characters in user-provided data before rendering it within JSON responses.
The technical implementation of this vulnerability occurs when the configuration utility processes user input through an undisclosed page that subsequently generates JSON responses. When malicious actors inject crafted payloads containing special characters such as quotes, backslashes, or script tags, the system fails to properly escape these values during the JSON response generation process. This improper handling creates an environment where attacker-controlled data can be interpreted as executable JavaScript code by web browsers. The vulnerability is classified under CWE-79 as a Cross-Site Scripting flaw, specifically manifesting as a reflected XSS attack vector that operates through the JSON response mechanism rather than traditional HTML injection methods.
The operational impact of CVE-2019-6599 extends beyond simple data exfiltration or session hijacking, as it provides attackers with the capability to execute arbitrary code within the context of the victim's browser session. This vulnerability can be exploited to perform actions such as stealing session cookies, modifying configuration settings, or redirecting users to malicious websites. The attack surface is particularly concerning for network infrastructure administrators who rely on the BIG-IP system for load balancing, application delivery, and security services. Successful exploitation could lead to complete compromise of the affected system, potentially allowing attackers to gain unauthorized access to sensitive network resources or disrupt critical application services.
Organizations should implement immediate mitigations including applying the latest security patches released by F5, which address the improper escaping mechanisms in the configuration utility. Network segmentation and access controls should be strengthened to limit exposure of the affected systems to untrusted networks. Additionally, implementing web application firewalls with XSS detection capabilities and regular security monitoring can help identify and prevent exploitation attempts. The vulnerability aligns with ATT&CK technique T1566.001 for credential access through spearphishing attachments, as attackers could use this vulnerability to establish persistent access through stolen credentials or session tokens. Regular security assessments and input validation reviews should be conducted to prevent similar issues in other components of the BIG-IP platform and ensure comprehensive protection against similar cross-site scripting vulnerabilities.