CVE-2019-6615 in BIG-IP
Summary
by MITRE
On BIG-IP 14.0.0-14.1.0.1, 13.0.0-13.1.1.4, 12.1.0-12.1.4, 11.6.1-11.6.3.4, and 11.5.2-11.5.8, Administrator and Resource Administrator roles might exploit TMSH access to bypass Appliance Mode restrictions on BIG-IP systems.
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Analysis
by VulDB Data Team • 09/12/2023
The vulnerability identified as CVE-2019-6615 represents a critical authorization bypass flaw within F5 BIG-IP systems that affects multiple major versions including 14.0.0 through 14.1.0.1, 13.0.0 through 13.1.1.4, 12.1.0 through 12.1.4, 11.6.1 through 11.6.3.4, and 11.5.2 through 11.5.8. This security weakness specifically targets the TMSH (Traffic Management Shell) access mechanisms and allows authenticated users with Administrator and Resource Administrator roles to circumvent the Appliance Mode restrictions that are designed to enforce security policies and system integrity controls.
The technical implementation of this vulnerability stems from insufficient access control validation within the TMSH interface of the BIG-IP system. When administrators or resource administrators execute commands through TMSH, the system fails to properly validate whether these operations should be permitted under the current appliance mode configuration. This flaw enables malicious actors with appropriate credentials to escalate their privileges and execute commands that would normally be restricted by the appliance mode policies. The vulnerability operates at the system-level access control layer where the distinction between authorized and restricted operations becomes blurred, creating a pathway for unauthorized system manipulation.
The operational impact of CVE-2019-6615 extends beyond simple privilege escalation as it fundamentally compromises the security posture of affected BIG-IP deployments. Attackers who successfully exploit this vulnerability can bypass critical security controls that are meant to prevent unauthorized modifications to system configurations, access restricted resources, and potentially gain deeper insights into the network infrastructure. The implications are particularly severe for organizations that rely on appliance mode as a primary security mechanism to prevent unauthorized access to sensitive network components and maintain compliance with security standards. This vulnerability directly undermines the principle of least privilege and could lead to complete system compromise if exploited by malicious actors.
Organizations affected by this vulnerability should implement immediate mitigations including applying the latest F5 security patches and hotfixes as recommended by the vendor. Network segmentation and monitoring should be enhanced to detect unauthorized TMSH access attempts, while privileged access controls should be strictly enforced through role-based access controls and multi-factor authentication. The vulnerability aligns with CWE-284 which describes improper access control issues, and represents a significant concern from an ATT&CK perspective as it enables privilege escalation techniques under the T1068 (Service Execution) and T1548.001 (Abuse Elevation Control Mechanism) tactics. Additionally, this vulnerability demonstrates the critical importance of proper input validation and access control enforcement in network infrastructure devices, particularly those handling sensitive traffic management functions within enterprise environments.