CVE-2019-18352 in FL NAT 2208
Summary
by MITRE
Improper access control exists on PHOENIX CONTACT FL NAT 2208 devices before V2.90 and FL NAT 2304-2GC-2SFP devices before V2.90 when using MAC-based port security.
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Analysis
by VulDB Data Team • 04/01/2024
The vulnerability identified as CVE-2019-18352 represents a critical improper access control flaw affecting PHOENIX CONTACT network devices, specifically the FL NAT 2208 and FL NAT 2304-2GC-2SFP models. This security weakness manifests in devices running firmware versions prior to V2.90, where the implementation of MAC-based port security fails to properly enforce access restrictions. The vulnerability stems from inadequate validation mechanisms that allow unauthorized network access through compromised or malicious MAC addresses, creating a significant entry point for potential attackers seeking to exploit the network infrastructure.
The technical implementation of this flaw involves the failure of the device's MAC address filtering system to maintain proper authentication boundaries for network ports. When MAC-based port security is enabled, the device should restrict network access to only those MAC addresses that have been explicitly authorized through the management interface. However, in vulnerable versions, the system does not adequately verify or enforce these restrictions, allowing unauthorized devices to potentially bypass the security controls. This weakness operates at the network layer where port security mechanisms are supposed to function as a first line of defense against unauthorized network access, effectively creating a backdoor for malicious actors who can leverage this flaw to gain network privileges.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially establish persistent network footholds within the infrastructure. Network administrators who rely on MAC-based port security for access control may find their security posture significantly weakened, as the vulnerability allows attackers to circumvent these protections entirely. The flaw particularly affects industrial network environments where PHOENIX CONTACT devices are commonly deployed, potentially compromising critical infrastructure operations. Attackers could exploit this vulnerability to perform man-in-the-middle attacks, network reconnaissance, or even escalate privileges within the network, depending on the overall security architecture and additional controls in place.
Organizations utilizing affected PHOENIX CONTACT devices should prioritize immediate firmware updates to V2.90 or later versions to remediate this vulnerability. The update process should be carefully planned to minimize operational disruption while ensuring complete protection against the identified flaw. Network segmentation strategies should be reviewed and enhanced to provide additional layers of protection, particularly in environments where the vulnerability may be exploited. Security monitoring systems should be configured to detect anomalous network behavior that might indicate exploitation attempts, including unusual MAC address changes or unauthorized network access patterns. This vulnerability aligns with CWE-284 which describes improper access control, and could potentially be leveraged through techniques described in the ATT&CK framework under network infiltration and privilege escalation tactics, emphasizing the need for comprehensive security remediation measures.