CVE-2018-17010 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_host_2g bandwidth.
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Analysis
by VulDB Data Team • 03/23/2020
The vulnerability identified as CVE-2018-17010 affects TP-Link TL-WR886N routers running specific firmware versions, presenting a significant security risk through a buffer overflow condition that can be exploited by authenticated attackers. This issue manifests when the router processes malformed JSON data submitted through the wireless wlan_host_2g bandwidth parameter, which falls under the category of improper input validation and memory handling within network services. The affected devices operate with firmware versions TL-WR886N 6.0 2.3.4 and TL-WR886N 7.0 1.1.0, indicating a targeted flaw in the router's web interface and service management components that handle wireless configuration parameters.
The technical flaw stems from inadequate bounds checking and memory allocation when processing JSON data submitted through the wireless configuration interface. When an authenticated user sends excessively long JSON payloads to the wlan_host_2g bandwidth parameter, the router's internal processing routines fail to properly validate the input length before attempting to parse and store the data. This condition creates a classic buffer overflow scenario where the application attempts to write more data into a fixed-length buffer than it can accommodate, leading to memory corruption that ultimately results in service crashes. The vulnerability operates at the application layer and specifically impacts the inetd service, HTTP daemon, DNS resolver, and UPnP service, demonstrating the widespread nature of the flaw's impact across multiple network functions.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. When router services crash, the device experiences temporary unavailability of network connectivity, DNS resolution, and UPnP functionality, which can severely impact network operations and user experience. The authenticated nature of the attack means that an attacker must first gain access to the router's administrative interface, typically through legitimate user credentials, which makes the vulnerability somewhat less critical than unauthenticated exploits but still represents a significant threat to network availability. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a specific implementation weakness in the router's JSON parsing routines that fail to enforce proper input length validation.
The security implications of CVE-2018-17010 align with several tactics described in the MITRE ATT&CK framework, particularly focusing on privilege escalation and denial of service operations. While the vulnerability requires authentication, it can be leveraged to maintain persistent access to network infrastructure by repeatedly crashing services and potentially causing the router to reboot, which may allow for additional exploitation opportunities. Network administrators should consider this vulnerability in the context of broader security monitoring efforts, as service disruption can serve as a cover for more sophisticated attacks or as a means to gain persistent access through repeated exploitation attempts. The flaw demonstrates how embedded network devices often lack proper input sanitization and memory management practices that are standard in enterprise-grade software development, highlighting the need for more robust security testing in consumer networking equipment.
Mitigation strategies for this vulnerability should include immediate firmware updates from TP-Link to address the buffer overflow condition in the affected router models. Network administrators should also implement monitoring solutions to detect unusual service disruption patterns that might indicate exploitation attempts, particularly focusing on HTTP and service restart events. The implementation of network segmentation and access control measures can limit the potential impact of successful exploitation by preventing unauthorized users from accessing the router's administrative interface. Additionally, regular security audits of network infrastructure should include assessment of embedded device firmware versions and vulnerability scanning to identify similar buffer overflow conditions in other network equipment. Organizations should also consider implementing network intrusion detection systems that can identify anomalous JSON data patterns or service disruption events that may indicate exploitation attempts targeting similar vulnerabilities in network infrastructure devices.