CVE-2017-15616 in WVR
Summary
by MITRE
TP-Link WVR, WAR and ER devices allow remote authenticated administrators to execute arbitrary commands via command injection in the new-interface variable in the phddns.lua file.
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Analysis
by VulDB Data Team • 12/22/2019
The CVE-2017-15616 vulnerability affects TP-Link WVR, WAR, and ER series network devices, representing a critical command injection flaw that enables remote authenticated administrators to execute arbitrary code on affected systems. This vulnerability resides within the phddns.lua file where the new-interface variable is improperly handled, creating an exploitable condition that can be leveraged by attackers who have already gained administrative access to the device. The flaw demonstrates a classic lack of input validation and sanitization that allows malicious commands to be injected into system calls without proper filtering or escaping mechanisms.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied input within the web interface configuration handling logic. When administrators configure network interfaces through the web management console, the new-interface parameter is directly passed to underlying system commands without proper validation or escaping. This design flaw aligns with CWE-77, which specifically addresses command injection vulnerabilities where untrusted data is incorporated into system commands without adequate protection mechanisms. The vulnerability exists because the device fails to implement proper input sanitization techniques that would prevent malicious payloads from being executed as part of legitimate system operations.
From an operational perspective, this vulnerability creates significant risk for network administrators who may unknowingly grant attackers access to their devices through legitimate administrative sessions. An attacker with valid administrative credentials can exploit this flaw to execute arbitrary commands with the privileges of the web server process, potentially leading to complete system compromise. The impact extends beyond simple command execution as the attacker can manipulate network configurations, access sensitive data, install malware, or establish persistent backdoors. This vulnerability directly maps to ATT&CK technique T1059.001, which covers command and script injection, and represents a critical escalation path for attackers already inside the network perimeter.
The exploitation of this vulnerability requires only authenticated access to the device's administrative interface, making it particularly dangerous as it can be leveraged by insiders or attackers who have obtained administrative credentials through other means. Security professionals should recognize this as a prime example of how seemingly benign input handling can create catastrophic security implications. The vulnerability affects multiple TP-Link device models and represents a systemic issue in the firmware's web interface implementation. Organizations should immediately implement mitigations including firmware updates from TP-Link, network segmentation to limit administrative access, and monitoring for suspicious administrative activities that might indicate exploitation attempts.
Mitigation strategies should focus on both immediate remediation and long-term security hardening. Device firmware updates from TP-Link address the root cause by implementing proper input validation and sanitization mechanisms for all user-supplied parameters. Network administrators should also implement principle of least privilege for administrative accounts, ensuring that only necessary personnel have access to device configuration interfaces. Additional protective measures include implementing network monitoring to detect unusual command execution patterns, configuring secure administrative access through VPNs or bastion hosts, and establishing regular security audits of network device configurations. The vulnerability highlights the importance of input validation in web applications and demonstrates how command injection flaws can be exploited even in environments where traditional network security controls are in place.