CVE-2018-15356 in ESP-200
Summary
by MITRE
An authenticated attacker can execute arbitrary code using command ejection in Eltex ESP-200 firmware version 1.2.0.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/16/2020
The vulnerability identified as CVE-2018-15356 represents a critical command injection flaw within the Eltex ESP-200 network security appliance firmware version 1.2.0. This issue arises from insufficient input validation and sanitization mechanisms within the device's web interface, specifically affecting the command execution functionality that allows administrators to perform system maintenance tasks through the graphical user interface. The vulnerability exists in the way the device processes user-supplied parameters when executing system commands, creating an avenue for malicious actors to inject arbitrary commands that will be executed with the privileges of the web application process. The flaw enables authenticated attackers who have gained access to the device's administrative interface to bypass normal security controls and execute arbitrary code on the underlying system. This command injection vulnerability stems from improper handling of user input within the firmware's command processing pipeline, where input parameters are directly concatenated into system command strings without adequate sanitization or escaping mechanisms.
The technical exploitation of this vulnerability requires an attacker to first authenticate to the device using valid administrative credentials, which then provides access to the web-based management interface where the command execution functionality is exposed. Once authenticated, the attacker can manipulate input fields within the web interface to inject malicious commands that will be executed by the system shell. The vulnerability's impact is amplified by the fact that the executed commands run with elevated privileges, potentially allowing full system compromise including privilege escalation to root level access. This flaw directly maps to CWE-77 which describes improper neutralization of special elements used in a command, and CWE-94 which covers improper control of generation of code. The command injection occurs in the context of the web application's execution environment, where user-provided data flows directly into system commands without proper validation or sanitization. The attack surface is further expanded by the fact that the vulnerability exists in the firmware's web interface, meaning that successful exploitation can occur through standard network protocols such as http or https without requiring physical access to the device.
The operational impact of this vulnerability extends beyond simple code execution, potentially allowing attackers to completely compromise the security posture of the network infrastructure device. An attacker with successful exploitation can gain access to sensitive system information, modify device configuration, install backdoors, or redirect network traffic through the compromised appliance. The vulnerability affects the integrity and availability of the network security device, potentially creating persistent access points for further attacks within the network infrastructure. Organizations using the affected Eltex ESP-200 firmware version 1.2.0 face significant risk of unauthorized access to their network security controls, as the compromised device could be used to monitor traffic, bypass security policies, or serve as a launch point for attacks against other network segments. This vulnerability particularly impacts enterprise and industrial network security deployments where such appliances are commonly used for firewall and network access control functions. The attack pattern aligns with ATT&CK technique T1059 which describes command and scripting interpreter, specifically focusing on the execution of system commands through legitimate interfaces.
Mitigation strategies for this vulnerability require immediate firmware updates from Eltex to address the command injection flaw through proper input validation and sanitization mechanisms. Organizations should implement network segmentation and access controls to limit administrative access to the device to only authorized personnel, reducing the attack surface for potential exploitation. Additional protective measures include monitoring network traffic for suspicious command execution patterns, implementing web application firewalls to detect and block malicious input, and establishing robust credential management practices including multi-factor authentication for administrative access. The remediation process should involve thorough testing of updated firmware to ensure that the vulnerability is properly addressed without introducing new issues. Network administrators should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures for handling potential compromise of network security appliances. The vulnerability demonstrates the critical importance of proper input validation in web applications and the necessity of regular firmware updates to address security vulnerabilities in network infrastructure devices.