CVE-2013-5219

Step 1: Crafting the Payload: The attacker constructs a malicious HTTP request containing a directory traversal payload. This payload typically includes the sequence ../ repeated to navigate up the directory tree, followed by the target file path (e.g., /etc/passwd).

Step 2: Sending the Request: The attacker sends the crafted HTTP request to the vulnerable HOT HOTBOX router.

Step 3: Request Processing: The router's web server receives the request and attempts to process the URI. Due to the vulnerability, the server fails to properly sanitize the input.

Step 4: File Access: The server, using the unsanitized path, attempts to open and serve the requested file (e.g., /etc/passwd).

Step 5: Information Disclosure: The router returns the contents of the requested file (e.g., /etc/passwd) in the HTTP response, providing the attacker with sensitive system information.

The vulnerability stems from a failure to properly sanitize user-supplied input when handling URI requests. Specifically, the router's web server does not adequately validate the path provided in the URI. By including ../ sequences in the request, an attacker can navigate outside the intended directory structure and access arbitrary files on the system. The root cause is a lack of input validation, allowing the attacker to manipulate the file path and bypass security controls. The webserver likely uses a function that constructs a file path based on the URI, and this function does not properly sanitize the input before using it to access the file system. This allows the attacker to traverse the directory structure.