CVE-2023-27359 in AX1800
Summary
by MITRE • 05/03/2024
TP-Link AX1800 hotplugd Firewall Rule Race Condition Vulnerability. This vulnerability allows remote attackers to gain access to LAN-side services on affected installations of TP-Link Archer AX21 routers. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the hotplugd daemon. The issue results from firewall rule handling that allows an attacker access to resources that should be available to the LAN interface only. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the root user. . Was ZDI-CAN-19664.
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Analysis
by VulDB Data Team • 08/06/2025
The CVE-2023-27359 vulnerability represents a critical race condition flaw in the hotplugd daemon component of TP-Link Archer AX21 routers, specifically affecting the AX1800 model. This vulnerability resides within the firewall rule handling mechanism that governs network traffic between the WAN and LAN interfaces. The flaw stems from improper synchronization during the processing of network events, creating a temporal window where firewall rules can be manipulated or bypassed. The vulnerability is particularly concerning because it allows unauthenticated remote exploitation, eliminating the need for prior authentication credentials to initiate the attack vector. This race condition occurs during the dynamic handling of network plug-and-play events, where the system fails to properly validate or enforce access controls when processing incoming network traffic.
The technical implementation of this vulnerability involves a classic race condition scenario where multiple threads or processes attempt to modify firewall rules simultaneously without proper locking mechanisms. The hotplugd daemon, responsible for managing dynamic network interface configurations, fails to maintain consistent state during rule application, creating opportunities for malicious actors to inject or modify firewall rules. This flaw specifically affects the LAN-side service accessibility controls, allowing remote attackers to bypass the intended network segmentation that should isolate internal network resources from external threats. The vulnerability enables attackers to gain access to services that should only be available through the LAN interface, effectively creating a backdoor into the internal network infrastructure. According to CWE-362, this represents a race condition vulnerability where concurrent operations can lead to inconsistent system states and unauthorized access.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with a potential pathway for privilege escalation and system compromise. Once an attacker gains access to LAN-side services, they can leverage this initial foothold to conduct further reconnaissance and potentially execute arbitrary code with root privileges. The vulnerability's exploitation can lead to complete system compromise, allowing attackers to modify router configurations, intercept network traffic, or establish persistent access points. This risk is exacerbated by the fact that the vulnerability affects the core network security mechanisms of the device, potentially allowing attackers to bypass all other security controls that should protect the internal network. The attack surface is particularly dangerous because it can be combined with other vulnerabilities to create more sophisticated exploitation chains, as noted in the original description.
Security professionals should implement immediate mitigations including firmware updates from TP-Link, network segmentation measures, and monitoring for unusual network traffic patterns. The vulnerability aligns with ATT&CK technique T1071.001 for application layer protocols and T1068 for local privilege escalation, making it a multi-faceted threat requiring comprehensive defensive measures. Organizations should also consider implementing network access control lists to restrict access to potentially vulnerable services and establish baseline network behavior monitoring to detect anomalous access patterns. The vulnerability demonstrates the critical importance of proper synchronization mechanisms in security-critical code and serves as a reminder of the risks associated with dynamic network configuration management in enterprise and consumer devices. Given the remote exploitation capability and lack of authentication requirements, immediate remediation actions are essential to prevent potential exploitation by threat actors.