CVE-2019-6646 in BIG-IP
Summary
by MITRE
On BIG-IP 11.5.2-11.6.4 and Enterprise Manager 3.1.1, REST users with guest privileges may be able to escalate their privileges and run commands with admin privileges.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-6646 represents a critical privilege escalation flaw within F5 BIG-IP systems operating within versions 11.5.2 through 11.6.4 and Enterprise Manager 3.1.1. This issue specifically targets REST API authentication mechanisms and allows authenticated users with guest privileges to exploit weaknesses in the system's access control implementation. The flaw exists in the way the BIG-IP system handles privilege validation during REST API operations, creating an avenue for lower-privileged users to gain administrative access and execute commands with full system privileges.
This vulnerability stems from inadequate input validation and privilege checking within the REST API interface of the BIG-IP system. The technical implementation fails to properly verify user permissions before executing sensitive operations, allowing guest-level users to manipulate API requests in ways that bypass normal access controls. The flaw specifically affects the system's ability to maintain proper authentication boundaries, enabling an attacker with minimal privileges to escalate their access level through carefully crafted API calls. This represents a classic example of improper privilege management and insufficient authorization checks that directly violates security principles of least privilege and principle of least privilege enforcement.
The operational impact of this vulnerability is severe as it allows attackers to gain complete administrative control over affected BIG-IP systems, potentially compromising the entire network infrastructure that relies on these load balancers and application delivery controllers. Once escalated to admin privileges, attackers can modify system configurations, access sensitive data, disable security features, and potentially establish persistent access points within the network. The vulnerability affects organizations using F5 BIG-IP systems in critical network infrastructure roles where load balancing, application delivery, and security services are provided. This creates a significant risk for organizations that depend on these systems for network security and application availability, as the compromise of a single system could provide attackers with a foothold to target other network segments.
Organizations should immediately implement mitigations including applying the official F5 security patches released for this vulnerability, which address the privilege escalation mechanism through proper input validation and enhanced authorization checks. Network segmentation should be implemented to limit access to BIG-IP systems to only authorized personnel, and monitoring should be enhanced to detect unusual API access patterns that may indicate privilege escalation attempts. The vulnerability aligns with CWE-284 which describes improper access control, and maps to ATT&CK technique T1068 which covers exploit for privilege escalation. Additionally, implementing multi-factor authentication for administrative access and regular security audits of API access controls will help reduce the risk exposure. Organizations should also review their current access control policies and ensure that guest users have minimal necessary privileges, as this vulnerability demonstrates the critical importance of maintaining strict access control boundaries even within authenticated user sessions.
The broader implications extend beyond immediate exploitation as this vulnerability highlights systemic issues in API security design and privilege management within enterprise security appliances. The flaw represents a failure in the principle of least privilege enforcement where the system does not adequately validate user permissions before executing privileged operations. This vulnerability type is particularly concerning in enterprise environments where BIG-IP systems serve as critical infrastructure components, as the compromise of these devices can lead to widespread network disruption and data breaches. The security implications underscore the need for comprehensive security testing of API interfaces and proper authorization validation mechanisms to prevent similar privilege escalation vulnerabilities from being exploited in other network infrastructure components.