Huawei HG255s Local File Inclusion Scanner

The Huawei HG255s is a widely used router that provides internet connectivity to residential and business environments. It is typically utilized by individuals and organizations who require reliable and steady internet access for various applications like web browsing, streaming, and networking. The device is popular for its ease of use, efficient performance, and support for multiple connections. Its features are designed to cater to both individual users and small to medium-sized enterprises that need efficient network solutions. It offers wireless connectivity, enabling users to connect multiple devices without needing physical cables. As technology advances, devices like the Huawei HG255s continue to play a crucial role in maintaining connectivity and ensuring smoother online operations.

Local File Inclusion (LFI) is a vulnerability that arises when a web application allows users to access files on the server. This vulnerability can be exploited when an external input is used to construct file paths. Attackers may utilize LFI to disclose sensitive files, execute arbitrary code, or escalate privileges on a vulnerable device. The vulnerability is severe because it doesn't require much technical knowledge to exploit and can be executed remotely by an unauthenticated attacker. LFI is commonly found in applications that dynamically include files based on user-controlled input. It poses a significant risk as personal information or system configurations may be exposed. In its most severe form, it could lead to full system compromise.

The technical aspects of this LFI vulnerability stem from the inadequate validation of HTTP requests by the Huawei HG255s. The GET request path includes traversal sequences (`..%2f`), which allow unauthorized access. The endpoint in question is susceptible because the system does not properly cleanse or check user inputs in file paths. This vulnerability specifically affects paths like `{{BaseURL}}/css/..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2fetc/passwd` and allows unauthorized users to retrieve sensitive system files. Matchers such as regular expressions and status codes help verify successful exploitation. The vulnerability underscores the importance of secure input validation and path normalization techniques.

If exploited, the LFI vulnerability could allow attackers to access sensitive internal files on the Huawei HG255s router. Malicious users could gain insight into configuration files, user credentials, or other sensitive data that can be used for further attacks. There is also potential for privilege escalation if sensitive information is leveraged to bypass authentication mechanisms. This exploitation can lead to system instability, exposure of sensitive data, or full control over the router by attackers. Addressing this vulnerability is crucial to maintaining the integrity and confidentiality of data stored or transmitted through the device.

REFERENCES

• https://cxsecurity.com/issue/WLB-2017090053
• https://www.youtube.com/watch?v=n02toTFkLOU