CVE-2017-17309 in HG255s-10
Summary
by MITRE
Huawei HG255s-10 V100R001C163B025SP02 has a path traversal vulnerability due to insufficient validation of the received HTTP requests, a remote attacker may access the local files on the device without authentication.
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Analysis
by VulDB Data Team • 03/27/2023
The Huawei HG255s-10 V100R001C163B025SP02 router firmware contains a critical path traversal vulnerability that stems from inadequate input validation within the HTTP request processing mechanism. This vulnerability resides in the device's web interface handling logic where user-supplied data is not properly sanitized before being used to construct file paths. The flaw allows an unauthenticated remote attacker to manipulate HTTP request parameters to traverse the file system and access sensitive local files that should remain protected. The vulnerability specifically affects the device's web server component which processes incoming requests without sufficient validation of directory traversal sequences such as ../ or ..\ that could be embedded within file paths or parameters. This weakness enables attackers to bypass normal access controls and potentially obtain confidential information, system configuration details, or even execute arbitrary code depending on the accessible file permissions. The impact extends beyond simple information disclosure as it represents a fundamental breakdown in the device's security model where authentication mechanisms are circumvented through manipulation of the HTTP protocol itself.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-22 Path Traversal and CWE-23 Improper Limitation of a Pathname to a Restricted Directory. Attackers can construct malicious HTTP requests that include directory traversal sequences in parameters such as file names, configuration paths, or other file-related inputs. When the device processes these requests, it fails to validate that the requested paths remain within the intended directory boundaries, allowing access to arbitrary files on the device's file system. The vulnerability is particularly concerning because it operates at the application layer HTTP protocol level, meaning that no authentication is required to exploit it. This characteristic makes it a prime target for automated scanning tools and makes it extremely difficult to detect in network traffic since the malicious requests appear to be legitimate HTTP operations. The device's web server implementation does not employ proper input sanitization or path validation techniques that would prevent such traversal attacks from succeeding.
The operational impact of this vulnerability is significant for network administrators and security professionals managing Huawei HG255s-10 devices. Remote attackers can potentially access sensitive configuration files, system logs, user credentials stored in plain text, or other confidential data that may be accessible through the device's file system. The vulnerability creates an attack surface that could be leveraged to escalate privileges or gain deeper access to the network infrastructure. Organizations relying on these devices for broadband access or home networking may face risks including unauthorized network access, data exfiltration, or potential compromise of the entire network segment. The vulnerability also increases the risk of lateral movement within networks where these devices serve as gateways, as attackers could potentially discover other network assets or credentials that could be used for further attacks. This flaw directly conflicts with the principle of least privilege and represents a failure in the device's secure coding practices. The vulnerability also aligns with ATT&CK technique T1083 File and Directory Discovery, as it enables attackers to enumerate the device's file system without authentication. Network monitoring tools may not immediately flag this attack vector since the HTTP requests appear legitimate, making detection more challenging. The exploitation could also facilitate other attack techniques such as T1566 Phishing with Malicious Attachments or T1059 Command and Scripting Interpreter if attackers can access files containing executable code or scripts.
Mitigation strategies for this vulnerability should include immediate firmware updates from Huawei to address the path traversal flaw, as well as network-level protections such as implementing web application firewalls that can detect and block directory traversal attempts in HTTP requests. Organizations should also consider restricting access to the device's web interface to trusted networks only and disabling unnecessary services or features that may expose additional attack vectors. Network segmentation and access controls should be implemented to limit the potential impact of a successful exploitation. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other network devices. The vulnerability highlights the importance of proper input validation and secure coding practices in embedded systems, particularly those handling network protocols. Device administrators should also implement monitoring solutions that can detect unusual HTTP request patterns that may indicate attempts to exploit path traversal vulnerabilities. Additionally, network administrators should regularly review and audit device configurations to ensure that default credentials are changed and that unnecessary services are disabled to reduce the overall attack surface. The vulnerability serves as a reminder of the critical importance of firmware security updates and the need for robust input validation in all network-connected devices, particularly those handling HTTP traffic and file system operations.