CVE-2017-6161 in BIG-IP
Summary
by MITRE
In F5 BIG-IP LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway, GTM, Link Controller, PEM, WebAccelerator software version 12.0.0 - 12.1.2, 11.6.0 - 11.6.1, 11.4.0 - 11.5.4, 11.2.1, when ConfigSync is configured, attackers on adjacent networks may be able to bypass the TLS protections usually used to encrypted and authenticate connections to mcpd. This vulnerability may allow remote attackers to cause a denial-of-service (DoS) attack via resource exhaustion.
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Analysis
by VulDB Data Team • 01/05/2023
The vulnerability described in CVE-2017-6161 affects F5 BIG-IP products across multiple modules including Local Traffic Manager AAM AFM Analytics APM ASM DNS Edge Gateway GTM Link Controller PEM and WebAccelerator. This issue specifically impacts versions 12.0.0 through 12.1.2 11.6.0 through 11.6.1 11.4.0 through 11.5.4 and 11.2.1 where ConfigSync functionality is enabled. The flaw represents a significant security weakness that undermines the cryptographic protections typically enforced by the system. The vulnerability exists in the mcpd daemon which handles management communications and is particularly concerning because it affects the fundamental security mechanisms that protect administrative access to the device.
The technical exploitation of this vulnerability occurs when attackers are positioned on adjacent network segments and can leverage the ConfigSync configuration to bypass normal TLS protections. This allows unauthorized access to the mcpd service which is responsible for managing the device's configuration and administrative functions. The bypass mechanism essentially allows attackers to establish connections without proper authentication or encryption, effectively rendering the TLS security layer ineffective for this critical management service. This represents a violation of the principle of least privilege and undermines the device's security posture.
From an operational impact perspective this vulnerability creates multiple attack vectors that can be leveraged for various malicious activities. The most immediate concern is the potential for denial-of-service attacks through resource exhaustion as mentioned in the description. Attackers could exploit this weakness to consume system resources and cause legitimate services to become unavailable. However the implications extend beyond simple DoS attacks since the bypass of TLS protections could potentially enable more sophisticated attacks including unauthorized configuration changes, data exfiltration, or privilege escalation within the network infrastructure. The vulnerability particularly affects enterprise environments where F5 BIG-IP appliances serve as critical network security components.
Security professionals should consider this vulnerability in the context of the ATT&CK framework where it relates to privilege escalation and defense evasion techniques. The vulnerability aligns with CWE-310 which addresses cryptographic issues and specifically concerns the improper enforcement of cryptographic protocols. Organizations should implement immediate mitigations including disabling ConfigSync when not required, implementing network segmentation to prevent adjacent network access, and applying the vendor-provided security patches. The vulnerability demonstrates the importance of proper configuration management and the principle that even well-secured systems can be compromised when administrative services are improperly exposed or protected.
The broader implications of CVE-2017-6161 highlight the critical need for network security teams to regularly audit their F5 BIG-IP configurations and ensure that management services are properly isolated from untrusted network segments. This vulnerability serves as a reminder that even seemingly minor configuration parameters can create significant security weaknesses that adversaries can exploit to gain unauthorized access to critical infrastructure components. The fact that this affects multiple modules within the F5 BIG-IP platform indicates a systemic issue that requires comprehensive remediation rather than isolated fixes to individual components. Organizations should also consider implementing network monitoring solutions to detect unusual patterns of access to the mcpd service that might indicate exploitation attempts.