CVE-2017-8217 in TP-LINK
Summary
by MITRE
TP-Link C2 and C20i devices through firmware 0.9.1 4.2 v0032.0 Build 160706 Rel.37961n have too permissive iptables rules, e.g., SNMP is not blocked on any interface.
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Analysis
by VulDB Data Team • 06/19/2022
The vulnerability identified as CVE-2017-8217 affects TP-Link C2 and C20i wireless routers and access points running firmware versions up to 0.9.1 4.2 v0032.0 Build 160706 Rel.37961n. This issue represents a significant security flaw in network device configuration that stems from overly permissive firewall rules implemented through iptables. The affected devices fail to properly restrict access to essential network services, creating potential attack vectors for malicious actors who might exploit this misconfiguration to gain unauthorized access to the network infrastructure. This vulnerability falls under the category of improper access control as defined by CWE-284, where the device fails to properly enforce access restrictions for network services.
The technical flaw manifests through the implementation of iptables rules that do not adequately filter incoming traffic to the Simple Network Management Protocol (SNMP) service across all network interfaces. SNMP is a critical network management protocol that allows administrators to monitor and manage network devices, but when left accessible without proper restrictions, it becomes a prime target for exploitation. The permissive firewall configuration means that SNMP traffic can be received on any interface, bypassing the intended security boundaries that should isolate management services from public network access. This misconfiguration creates a scenario where unauthorized parties could potentially query device information, modify configurations, or launch further attacks against the network infrastructure.
The operational impact of this vulnerability extends beyond simple network management concerns to encompass broader security implications for enterprise and home network environments. Attackers who discover devices with this vulnerability could exploit the open SNMP access to gather sensitive information about the network topology, device configurations, and potentially gain access to additional network resources. The vulnerability creates a persistent security risk since the affected firmware versions remain active on numerous devices in the field, and the issue affects the fundamental network security posture of these devices. This weakness aligns with ATT&CK technique T1046 which involves network service scanning and can enable further lateral movement within networks. The vulnerability also relates to CWE-310 which addresses cryptographic weaknesses, as the lack of proper access controls creates an environment where sensitive information can be exposed.
Mitigation strategies for CVE-2017-8217 require immediate attention from network administrators responsible for TP-Link C2 and C20i devices. The most effective approach involves updating firmware to versions that properly implement iptables rules to restrict SNMP access to authorized management interfaces only. Network administrators should also implement additional network segmentation measures to isolate these devices from critical network segments. The recommended firewall configuration should explicitly block SNMP traffic on all interfaces except those specifically designated for management access, typically restricted to internal network segments with proper authentication mechanisms. Organizations should conduct comprehensive network audits to identify all affected devices and implement monitoring to detect unauthorized access attempts to SNMP services. This vulnerability demonstrates the critical importance of proper firewall rule implementation and the potential consequences of insufficient network segmentation, as outlined in industry best practices for network security management and the NIST Cybersecurity Framework.