CVE-2019-13271 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. They forward ARP requests, which are sent as broadcast packets, between the host and the guest networks. To use this leakage as a direct covert channel, the sender can trivially issue an ARP request to an arbitrary computer on the network. (In general, some routers restrict ARP forwarding only to requests destined for the network's subnet mask, but these routers did not restrict this traffic in any way. Depending on this factor, one must use either the lower 8 bits of the IP address, or the entire 32 bits, as the data payload.)
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Analysis
by VulDB Data Team • 12/07/2023
The CVE-2019-13271 vulnerability affects Edimax BR-6208AC V1 wireless routers where insufficient network compartmentalization exists between host and guest networks established by the same device. This security flaw represents a critical failure in network segmentation principles that violates fundamental cybersecurity practices for isolating sensitive network environments from less trusted zones. The vulnerability stems from the router's improper handling of Address Resolution Protocol (ARP) traffic between segmented network domains, creating an unintended communication pathway that undermines the security boundary between networks.
The technical implementation of this vulnerability exploits the router's failure to properly filter ARP broadcast traffic between network segments. When ARP requests are forwarded indiscriminately between host and guest networks, attackers can leverage this behavior to establish covert communication channels. This flaw directly corresponds to CWE-693 Protection Mechanism Failure, as the router fails to implement adequate network isolation controls. The vulnerability operates at the network layer of the OSI model, specifically affecting the data link layer protocols that govern device communication within local networks.
The operational impact of this vulnerability is significant as it enables attackers to perform network reconnaissance and potentially exfiltrate information across network boundaries. An attacker can trivially send ARP requests to arbitrary computers on the network, effectively using the router as a medium for cross-segment communication. The vulnerability's effectiveness depends on the specific network configuration where some routers restrict ARP forwarding to subnet mask destinations while others, like the affected Edimax models, forward all ARP traffic without restriction. This creates a data payload transmission mechanism where either the lower 8 bits or full 32-bit IP address can be utilized for covert data transmission, depending on the network's addressing scheme.
This vulnerability aligns with several ATT&CK framework techniques including T1046 Network Service Scanning and T1566 Credential Access Through Network Sniffing, as it enables unauthorized network discovery and potential information leakage. The flaw essentially transforms a legitimate network protocol into an attack vector, allowing for information disclosure and potential privilege escalation. Organizations using these routers face increased risk of internal network compromise, as the vulnerability enables attackers to bypass network segmentation controls that should prevent communication between different network zones. The lack of proper ARP filtering mechanisms represents a fundamental design flaw that violates basic network security principles and exposes organizations to lateral movement attacks.
Mitigation strategies should include implementing proper ARP filtering rules on the affected routers, disabling unnecessary ARP forwarding between network segments, and deploying network monitoring solutions to detect anomalous ARP traffic patterns. Network administrators should also consider upgrading to router firmware versions that address this specific vulnerability and implement additional network segmentation controls using VLANs or other isolation mechanisms. The vulnerability highlights the importance of proper network architecture design and the necessity of implementing defense-in-depth strategies that include multiple layers of network protection beyond simple firewall rules.