CVE-2017-8220 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 remote code execution with a single HTTP request by placing shell commands in a "host=" line within HTTP POST data.
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Analysis
by VulDB Data Team • 06/19/2022
The TP-Link C2 and C20i wireless routers represent a significant security vulnerability classified as CVE-2017-8220, which allows remote attackers to execute arbitrary code on affected devices through a single HTTP request. This vulnerability specifically targets the web-based management interface of these networking devices, exploiting a critical input validation flaw in the handling of HTTP POST data. The vulnerability affects firmware versions up to 0.9.1 4.2 v0032.0 Build 160706 Rel.37961n, making a substantial portion of these devices susceptible to exploitation. The flaw resides in how the device processes the "host=" parameter within HTTP POST requests, which is processed without proper sanitization or validation, creating a direct path for command injection attacks.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with CWE-77 and CWE-94, which respectively address command injection and code injection flaws in software systems. Attackers can craft malicious HTTP POST requests containing shell commands within the host parameter, which are then executed by the device's underlying operating system. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting the use of shell commands to gain unauthorized access and control over the affected systems. The vulnerability's remote nature means that attackers do not require physical access or local network presence to exploit the flaw, making it particularly dangerous for enterprise and home network environments.
The operational impact of CVE-2017-8220 extends beyond simple unauthorized access, as successful exploitation can lead to complete device compromise, including persistent backdoor installation, data exfiltration, and potential use as a pivot point for further attacks within the network. Network administrators face significant challenges in detecting such attacks since they occur through legitimate HTTP traffic patterns, making them difficult to distinguish from normal device operations. The vulnerability affects not only individual devices but can potentially compromise entire network infrastructures, especially when multiple vulnerable devices exist within the same network. Organizations using these devices are at risk of experiencing service disruption, data breaches, and unauthorized network access that could lead to more sophisticated attacks.
Mitigation strategies for CVE-2017-8220 should include immediate firmware updates from TP-Link to address the vulnerability, as well as network segmentation to limit the potential impact of exploitation. Security professionals should implement network monitoring to detect anomalous HTTP POST traffic patterns and consider disabling unnecessary web management interfaces. The vulnerability highlights the importance of input validation and proper sanitization of user-supplied data, which aligns with security best practices outlined in NIST SP 800-160 and OWASP Top 10. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures to address potential compromises. Given the remote nature of the vulnerability, continuous network monitoring and regular security assessments are essential to maintain defense in depth against similar threats.