CVE-2019-13267 in Archer C3200 V1
Summary
by MITRE
TP-Link Archer C3200 V1 and Archer C2 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-2019-13267 affects TP-Link Archer C3200 V1 and Archer C2 V1 wireless routers, representing a critical security flaw in network compartmentalization mechanisms. This issue stems from inadequate isolation between host and guest networks within the same device, creating a pathway for unauthorized data transfer across network boundaries that should remain logically separated. The vulnerability specifically exploits the Internet Group Management Protocol (IGMP) implementation within these routers, which governs how multicast traffic is managed across network segments.
The technical implementation of this flaw involves a sophisticated manipulation of the IGMP protocol's group membership functions. When data needs to be transferred from the host network to the guest network, the malicious sender must first join an IGMP group, then immediately leave it. Following this departure, the router generates an IGMP Membership Query packet containing the group IP address in its payload field. This group IP field becomes the vehicle for data transmission, and because it is completely controlled by the sender, it allows arbitrary data to be smuggled across network boundaries. The vulnerability operates at the network layer, specifically exploiting IGMP version 2 or 3 protocol implementations that are commonly found in consumer-grade routers.
The operational impact of this vulnerability is severe as it fundamentally undermines the security model of guest network isolation that network administrators rely upon for protecting sensitive host networks. Attackers can leverage this flaw to exfiltrate data from the host network to the guest network, potentially accessing confidential information, credentials, or system data that should remain isolated. This compromise represents a direct violation of network security principles and can enable lateral movement within corporate or residential environments where guest networks are used as a security boundary. The vulnerability is particularly dangerous because it requires no special privileges or authentication to exploit, making it accessible to any attacker with network access to the affected device.
This vulnerability maps directly to CWE-668, which describes "Exposure of Resource to Wrong Sphere," and aligns with ATT&CK technique T1046 for Network Service Scanning and T1566 for Phishing with Malicious Attachments, as it enables attackers to bypass network segmentation controls. The flaw also relates to ATT&CK technique T1071.004 for Application Layer Protocol: DNS, since the compromised group IP field could be used to encode DNS tunneling data. Additionally, this vulnerability is classified under the broader category of insufficient network segmentation, which is a common weakness in IoT and networking devices where security boundaries are not properly enforced.
Mitigation strategies for CVE-2019-13267 should focus on both immediate and long-term solutions. The most effective immediate measure is to upgrade firmware to versions that properly implement IGMP group management without allowing arbitrary data transmission through the group IP field. Network administrators should also implement additional monitoring and intrusion detection systems that can identify unusual IGMP traffic patterns that may indicate exploitation attempts. Layered defenses including firewall rules that restrict IGMP traffic between network segments, network access control policies, and regular security audits of network infrastructure can help prevent exploitation. The vulnerability highlights the importance of proper protocol implementation and network security boundary enforcement, particularly in consumer networking equipment where firmware updates may not be regularly applied by end users, making the device vulnerable to exploitation for extended periods.