CVE-2018-20218 in ENC-400
Summary
by MITRE
An issue was discovered on Teracue ENC-400 devices with firmware 2.56 and below. The login form passes user input directly to a shell command without any kind of escaping or validation in /usr/share/www/check.lp file. An attacker is able to perform command injection using the "password" parameter in the login form.
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Analysis
by VulDB Data Team • 09/24/2024
The vulnerability identified as CVE-2018-20218 affects Teracue ENC-400 network security devices running firmware versions 2.56 and earlier, representing a critical command injection flaw that directly compromises device security. This vulnerability resides within the /usr/share/www/check.lp file where the authentication mechanism fails to properly sanitize user input, creating an exploitable path for malicious actors to execute arbitrary commands on the affected system. The specific weakness occurs in the password parameter processing within the login form, where input validation and sanitization mechanisms are completely absent, allowing attackers to inject shell commands that are subsequently executed with the privileges of the web server process.
The technical exploitation of this vulnerability follows a command injection pattern that aligns with CWE-77 and CWE-89, which classify improper neutralization of special elements used in commands. The flaw exists because the system directly incorporates user-supplied data into shell execution contexts without any form of input filtering or escaping mechanisms. When an attacker submits malicious input through the password field during authentication, the system treats this input as executable commands rather than simple credential data, enabling complete system compromise. This type of vulnerability represents a classic example of insufficient input validation that allows attackers to bypass authentication mechanisms and gain unauthorized access to device functionality.
The operational impact of this vulnerability extends beyond simple authentication bypass to encompass complete system compromise, as the executed commands can leverage the privileges of the web server process which typically has elevated access to system resources. Attackers can potentially execute commands with root privileges, allowing them to modify system configurations, extract sensitive data, install backdoors, or disable security features. The vulnerability affects the device's core authentication functionality, meaning that unauthorized access to the device's management interface becomes trivial for attackers who understand command injection techniques. This compromise can lead to network infiltration, data exfiltration, and potential use as a pivot point for attacking other systems within the network perimeter.
Mitigation strategies for CVE-2018-20218 should prioritize immediate firmware updates to versions that address the command injection vulnerability, as this represents the most effective defense against exploitation. Organizations should also implement network segmentation to limit access to these devices and deploy intrusion detection systems that can identify suspicious command execution patterns. Additional protective measures include disabling unnecessary web services, implementing strong access controls, and conducting regular security assessments to identify similar vulnerabilities in network infrastructure devices. The vulnerability demonstrates the importance of proper input validation and output encoding practices as outlined in the OWASP Top Ten and aligns with ATT&CK technique T1059 for command and script injection, emphasizing the need for comprehensive application security controls in networked devices.