CVE-2018-17013 in TL-WR886N
Summary
by MITRE
An issue was discovered on TP-Link TL-WR886N 6.0 2.3.4 and TL-WR886N 7.0 1.1.0 devices. Authenticated attackers can crash router services (e.g., inetd, HTTP, DNS, and UPnP) via long JSON data for protocol wan wan_rate.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/23/2020
The vulnerability CVE-2018-17013 affects TP-Link TL-WR886N wireless routers running firmware versions 6.0 2.3.4 and 7.0 1.1.0, representing a critical denial-of-service condition that can be exploited by authenticated attackers. This issue stems from improper input validation within the router's web interface management system, specifically when processing JSON data for the wan_rate protocol configuration. The flaw manifests when an authenticated user submits excessively long JSON payloads to the wan_rate parameter, causing the affected services to become unresponsive or crash entirely. The impacted services include inetd, HTTP, DNS, and UPnP daemons that are essential for the router's normal operation and network connectivity.
The technical root cause of this vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient validation occurs before copying data into fixed-length buffers. In this case, the router's firmware fails to properly validate the length of JSON data submitted for the wan_rate parameter, allowing malicious input to exceed allocated buffer space. When the system attempts to process this oversized JSON data, it triggers memory corruption that results in service crashes and complete disruption of router functionality. The vulnerability demonstrates characteristics of CWE-707, indicating improper handling of input data that leads to unexpected program behavior and system instability.
From an operational perspective, this vulnerability poses significant risks to network availability and security infrastructure. The authenticated nature of the attack means that an attacker must first gain access to the router's administrative interface, which typically requires valid credentials. However, once inside, the attacker can leverage this flaw to systematically disrupt network services, potentially causing extended outages for connected devices. The impact extends beyond simple service disruption as the crash of critical services like DNS and UPnP can affect the entire network's ability to function properly, particularly in environments where these services are essential for device discovery and network communication. This vulnerability can be particularly dangerous in enterprise or home office environments where router reliability is crucial for business continuity.
Mitigation strategies for CVE-2018-17013 should focus on both immediate remediation and long-term security hardening measures. The most effective immediate solution involves updating the router firmware to versions that properly validate JSON input lengths and implement appropriate buffer management techniques. Network administrators should also consider implementing access controls that limit administrative access to trusted users only, as well as monitoring for unusual authentication patterns that might indicate unauthorized access attempts. Additionally, the implementation of network segmentation and intrusion detection systems can help identify and contain potential exploitation attempts. This vulnerability relates to ATT&CK technique T1072 which involves software deployment methods that can be used to establish persistent access to systems, while also demonstrating the importance of input validation controls as outlined in the OWASP Top 10 security principles. Organizations should also implement regular vulnerability assessments and penetration testing to identify similar issues in other network infrastructure components that might be susceptible to similar buffer overflow conditions.