CVE-2019-13265 in DIR-825AC G1
Summary
by MITRE
D-link DIR-825AC G1 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-2019-13265 vulnerability affects D-Link DIR-825AC G1 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 security best practices for wireless access point configurations. The vulnerability stems from the router's improper handling of Address Resolution Protocol traffic between logically separated network zones, creating an unintended communication pathway that undermines the purpose of guest network isolation.
The technical flaw manifests through the router's forwarding of broadcast ARP requests between host and guest networks without proper access control or filtering mechanisms. This behavior directly contravenes established network security paradigms where guest networks should be completely isolated from host networks to prevent lateral movement and information leakage. The vulnerability operates at the data link layer of the OSI model, specifically exploiting the ARP protocol's broadcast nature to create a covert communication channel. According to CWE-668, this represents an insufficient compartmentalization vulnerability where the system fails to properly separate distinct security domains.
The operational impact of this vulnerability is significant as it enables attackers to establish a direct covert channel between network segments that should remain isolated. An attacker can trivially issue ARP requests to arbitrary computers on the network, effectively using the router's improper forwarding behavior as a data exfiltration mechanism. The attack vector can leverage either the lower 8 bits or entire 32-bit IP address space as data payloads depending on the specific network configuration, providing flexible communication capabilities. This vulnerability directly maps to ATT&CK technique T1046 which involves network service scanning and reconnaissance activities that can be performed through improper network segmentation.
The security implications extend beyond simple information leakage to potentially enable more sophisticated attacks including network reconnaissance, credential harvesting, and lateral movement within the compromised network environment. The vulnerability essentially transforms a security feature designed to protect network isolation into a mechanism for bypassing those protections. Organizations using these routers face increased risk of unauthorized access and data breaches, particularly in environments where guest network access is intended to provide restricted connectivity while maintaining separation from primary network resources. The flaw demonstrates a fundamental lack of proper network architecture design and access control implementation that violates basic security engineering principles.
Mitigation strategies should focus on immediate firmware updates from D-Link to address the improper ARP forwarding behavior, followed by network segmentation reviews to ensure proper isolation between host and guest networks. Network administrators should implement additional access control measures including firewall rules that prevent ARP traffic between network segments, and consider disabling guest network functionality if not required. The vulnerability highlights the importance of proper network design principles and the necessity of regular security assessments to identify and remediate similar configuration flaws that could compromise network security boundaries.