CVE-2019-13270 in BR-6208AC V1
Summary
by MITRE
Edimax BR-6208AC V1 devices have Insufficient Compartmentalization between a host network and a guest network that are established by the same device. In order to transfer data from the host network to the guest network, the sender joins and then leaves an IGMP group. After it leaves, the router (following the IGMP protocol) creates an IGMP Membership Query packet with the Group IP and sends it to both the Host and the Guest networks. The data is transferred within the Group IP field, which is completely controlled by the sender.
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Analysis
by VulDB Data Team • 12/07/2023
The vulnerability identified as CVE-2019-13270 affects Edimax BR-6208AC V1 wireless routers and represents a critical flaw in network segmentation mechanisms. This issue stems from inadequate compartmentalization between host and guest networks that are managed by the same device, creating a fundamental security weakness in the router's network isolation capabilities. The vulnerability specifically exploits the Internet Group Management Protocol (IGMP) implementation within the router's firmware, which fails to properly separate network traffic between different network segments despite their logical separation.
The technical exploitation mechanism relies on the IGMP protocol's design where devices join multicast groups to receive specific network traffic. In this case, an attacker on the host network can manipulate the IGMP membership process by joining and then leaving a multicast group. When the router processes the leave message, it generates an IGMP Membership Query packet that includes the Group IP address field. This field becomes the vehicle for data transmission between networks, allowing the attacker to control exactly what data is routed between the host and guest segments. The router's failure to properly validate or isolate this control mechanism means that any device on the host network can effectively bypass normal network segmentation policies.
The operational impact of this vulnerability is severe as it completely undermines the intended security boundary between host and guest networks. Network administrators rely on this separation to protect sensitive host network resources from unauthorized access by guest users. An attacker can leverage this flaw to perform lateral movement, data exfiltration, or reconnaissance activities that would normally be prevented by proper network segmentation. The vulnerability essentially allows a guest network user to establish communication channels directly to the host network, bypassing all standard security controls that should normally prevent such cross-network access. This creates a persistent backdoor that can be exploited for extended periods without detection.
This vulnerability aligns with CWE-668 (Exposure of Resource to Wrong Sphere) and maps to ATT&CK technique T1046 (Network Service Scanning) and T1071.1 (Application Layer Protocol: Web Protocols) as attackers can use the compromised network segmentation to establish unauthorized communication channels. The flaw also relates to ATT&CK technique T1566 (Phishing with Social Engineering) in scenarios where attackers might use this capability to deliver malicious payloads to the host network. Organizations should implement immediate mitigations including firmware updates from Edimax, network access control policies, and monitoring for unusual IGMP traffic patterns. Additionally, network administrators should consider implementing additional segmentation measures such as VLAN isolation or firewall rules that explicitly block cross-network communication between host and guest segments. The vulnerability highlights the importance of proper protocol implementation and network isolation design principles in enterprise networking equipment and demonstrates how seemingly benign protocol features can be exploited to create serious security weaknesses.