CVE-2018-17007 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 wireless wlan_wds_2g ssid.
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Analysis
by VulDB Data Team • 03/23/2020
The vulnerability CVE-2018-17007 represents a critical buffer overflow condition affecting TP-Link TL-WR886N wireless routers running specific firmware versions. This issue manifests when authenticated attackers submit excessively long JSON data to the wireless wlan_wds_2g ssid parameter, causing the router's services to crash and potentially leading to complete service disruption. The affected devices operate with firmware versions 6.0 2.3.4 and 7.0 1.1.0, indicating a widespread issue within the TP-Link product line that requires immediate attention from network administrators and security professionals.
The technical flaw stems from inadequate input validation within the router's web interface handling mechanism. When processing the wlan_wds_2g ssid parameter, the system fails to properly sanitize or limit the length of incoming JSON data, creating a classic buffer overflow scenario. This vulnerability operates at the application layer and specifically targets the inetd service and related network services such as HTTP, DNS, and UPnP. The flaw allows attackers to exploit the lack of proper bounds checking, enabling them to overwrite adjacent memory locations and cause the targeted services to terminate unexpectedly or crash entirely.
The operational impact of this vulnerability extends beyond simple service disruption, creating potential security risks for network infrastructure. When router services crash, they may become unavailable to legitimate users, effectively creating a denial of service condition that can persist until manual intervention occurs. Network administrators face significant challenges in maintaining service availability, particularly in environments where these devices serve as primary network gateways. The vulnerability's authenticated nature means that only users with valid credentials can exploit it, but this does not mitigate the risk since credential compromise can occur through various attack vectors including phishing, password reuse, or weak authentication practices. The affected services including HTTP and DNS create cascading effects that can impact entire network operations, while UPnP service disruption can prevent legitimate device communication and network management functions.
Mitigation strategies should focus on immediate firmware updates from TP-Link, which would address the underlying buffer overflow condition through proper input validation and bounds checking implementations. Network administrators should also implement monitoring solutions to detect unusual service termination patterns and establish automated alerting for router service disruptions. Additional defensive measures include restricting administrative access to only necessary personnel, implementing strong authentication mechanisms, and conducting regular vulnerability assessments of network infrastructure. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a typical example of how insufficient input validation creates opportunities for service disruption attacks. Organizations should also consider implementing network segmentation strategies to limit the potential impact of such vulnerabilities and ensure that critical network services maintain redundancy and failover capabilities to prevent complete service outages. The ATT&CK framework categorizes this vulnerability under the service disruption category, where adversaries can leverage weak input validation to create availability issues that compromise network reliability and business continuity.