CVE-2019-7253 in Linear eMerge E3
Summary
by MITRE
Linear eMerge E3-Series devices allow Directory Traversal.
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Analysis
by VulDB Data Team • 10/15/2023
The Linear eMerge E3-Series devices represent a line of network security appliances designed for enterprise environments, specifically targeting industrial control systems and critical infrastructure deployments. These devices function as network security gateways that manage and monitor traffic between different network segments while providing authentication and access control services. The vulnerability identified as CVE-2019-7253 manifests as a directory traversal flaw that allows unauthorized users to access files and directories outside the intended scope of the device's file system. This type of vulnerability falls under the Common Weakness Enumeration category CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical implementation of this vulnerability stems from inadequate input validation within the device's web interface and file handling mechanisms. When processing file requests or directory navigation commands, the device fails to properly sanitize user-supplied input, allowing attackers to manipulate file paths through special sequences such as ../ or ..\ that would normally be restricted. This weakness enables an attacker to navigate the file system beyond the intended boundaries and potentially access sensitive configuration files, system binaries, or other restricted resources. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication, making it accessible to any attacker who can reach the device's network interface. The flaw affects the device's web-based management interface and potentially other network services that handle file operations, creating multiple attack vectors for exploitation.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can lead to complete system compromise and unauthorized privilege escalation. An attacker who successfully exploits this directory traversal vulnerability could gain access to sensitive system files, including configuration data, authentication credentials, and potentially system binaries that could be modified to establish persistent access. The vulnerability creates a pathway for attackers to conduct reconnaissance activities, gather intelligence about the device's configuration and network topology, and potentially escalate privileges to gain administrative control over the device. This poses significant risks to industrial control systems where the eMerge E3-Series devices are deployed, as unauthorized access to these security appliances could compromise the integrity of the entire network security infrastructure. The attack surface is further expanded when considering that these devices often operate in environments where network segmentation and access controls are critical for maintaining operational security.
Mitigation strategies for CVE-2019-7253 should encompass both immediate defensive measures and long-term architectural improvements. Organizations should prioritize applying vendor-provided security patches and firmware updates as soon as they become available, as these typically contain fixes for the directory traversal vulnerability. Network segmentation and access control measures should be implemented to limit direct access to the device's management interfaces, reducing the attack surface available to potential adversaries. The principle of least privilege should be enforced by restricting administrative access to only necessary personnel and implementing multi-factor authentication for all management activities. Additionally, network monitoring and intrusion detection systems should be configured to detect suspicious file access patterns and directory traversal attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in the device's configuration and to ensure that the implemented controls remain effective against evolving attack techniques. The vulnerability also highlights the importance of secure coding practices and input validation in network security appliances, aligning with ATT&CK framework techniques that emphasize privilege escalation and credential access through exploitation of software vulnerabilities.