CVE-2017-8219 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 allow DoSing the HTTP server via a crafted Cookie header to the /cgi/ansi URI.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/19/2022
The vulnerability CVE-2017-8219 affects TP-Link C2 and C20i wireless access point devices running firmware versions up to 0.9.1 4.2 v0032.0 Build 160706 Rel.37961n. This represents a denial of service condition that specifically targets the device's HTTP server implementation through manipulation of the Cookie header parameter when accessing the /cgi/ansi URI endpoint. The flaw demonstrates a classic buffer overflow or input validation weakness that allows remote attackers to disrupt legitimate service availability without requiring authentication or specialized privileges.
The technical implementation of this vulnerability stems from inadequate input sanitization within the web server component of these devices. When the HTTP server processes a request containing a specially crafted Cookie header value directed at the /cgi/ansi URI, the device fails to properly validate or limit the length and content of the cookie data. This processing error creates a condition where the device's memory management becomes compromised, leading to service disruption or complete system unavailability. The vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations, and potentially maps to CWE-400, representing unchecked resource consumption through malformed input processing.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network infrastructure availability. In enterprise or industrial environments where these devices serve as critical network access points, such a denial of service condition could result in significant operational downtime and require immediate remediation efforts. The vulnerability's remote exploitability means that attackers can trigger the condition from outside the network perimeter, making it particularly concerning for organizations with limited network segmentation. According to ATT&CK framework domain T1499, this vulnerability represents a network denial of service technique that can be classified under the category of resource consumption attacks targeting network infrastructure components.
Mitigation strategies for CVE-2017-8219 should prioritize immediate firmware updates from TP-Link to address the underlying implementation flaw in the HTTP server component. Network administrators should also implement network segmentation and access controls to limit exposure of these devices to untrusted networks. Additional protective measures include monitoring for unusual HTTP request patterns targeting the /cgi/ansi URI and implementing rate limiting mechanisms to prevent rapid exploitation attempts. The vulnerability highlights the importance of proper input validation in embedded web server implementations and underscores the necessity of regular firmware updates to address security weaknesses in network infrastructure devices. Organizations should also consider implementing network intrusion detection systems capable of identifying and blocking malformed cookie headers that could trigger similar vulnerabilities in other networked devices.