CVE-2017-8116 in RUT9XX
Summary
by MITRE
The management interface for the Teltonika RUT9XX routers (aka LuCI) with firmware 00.03.265 and earlier allows remote attackers to execute arbitrary commands with root privileges via shell metacharacters in the username parameter in a login request.
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Analysis
by VulDB Data Team • 10/22/2019
The CVE-2017-8116 vulnerability represents a critical remote code execution flaw in the Teltonika RUT9XX series routers that affects firmware versions up to 00.03.265. This vulnerability exists within the LuCI management interface, which serves as the web-based administrative portal for these industrial-grade networking devices. The vulnerability stems from improper input validation and sanitization within the authentication mechanism, specifically targeting the username parameter in login requests. Attackers can exploit this weakness by injecting shell metacharacters into the username field, which then gets processed without adequate sanitization, leading to arbitrary command execution with root privileges. The impact is particularly severe because these routers are commonly deployed in industrial environments, often in remote locations, making them attractive targets for cybercriminals seeking persistent access to critical infrastructure networks.
The technical exploitation of this vulnerability follows a classic command injection pattern that aligns with CWE-77 and CWE-94 categories, where user-supplied input is directly incorporated into shell commands without proper validation or escaping. When a malicious user submits a login request containing shell metacharacters such as semicolons, ampersands, or backticks within the username parameter, the LuCI interface processes this input directly in the command execution context. This flaw enables attackers to execute arbitrary system commands with the highest privilege level available, effectively granting them complete control over the router's operating system. The vulnerability demonstrates poor input validation practices and highlights the dangerous consequences of concatenating user input directly into shell commands, which is a fundamental security anti-pattern that violates secure coding principles.
The operational impact of CVE-2017-8116 extends far beyond simple unauthorized access, as it provides attackers with complete administrative control over affected routers. In industrial settings where these devices are commonly deployed, this vulnerability can enable attackers to manipulate network traffic, redirect connections, disable security features, or establish persistent backdoors for future access. The remote nature of the exploit means that attackers can target these devices from anywhere on the internet without requiring physical access or local network presence. This vulnerability also aligns with several MITRE ATT&CK techniques including T1059 for command and scripting interpreter and T1078 for valid accounts, as attackers can leverage the compromised router to maintain persistent access and move laterally within networks. The implications are particularly concerning for critical infrastructure sectors where these routers often serve as gateways to industrial control systems and networked devices.
Organizations affected by this vulnerability should immediately implement mitigation strategies including firmware updates to versions 00.03.266 or later, which contain the necessary patches to address the command injection flaw. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while monitoring systems should be deployed to detect anomalous login patterns or unusual network behavior that might indicate exploitation attempts. Additionally, administrators should consider disabling unnecessary web management interfaces when not actively required, implementing strong authentication mechanisms, and regularly auditing router configurations to identify potential security weaknesses. The vulnerability underscores the importance of secure input validation and proper sanitization of user-supplied data in web applications, particularly those handling administrative functions where privilege escalation risks are significantly elevated.