CVE-2013-5220

Step 1: Target Identification: The attacker identifies a HOT HOTBOX router with software version 2.1.11 or earlier accessible on the network. Step 2: Payload Crafting: The attacker crafts a malicious HTTP POST request. This request is designed to contain a payload that exceeds the expected input buffer size of the goform/login handler. Step 3: Request Delivery: The attacker sends the crafted HTTP POST request to the goform/login endpoint of the target router (e.g., http://<router_ip>/goform/login). Step 4: Vulnerability Trigger: The router's goform/login handler receives the malicious POST data. Due to the lack of input validation, the oversized data overwrites the allocated buffer. Step 5: Device Crash: The overwritten data corrupts critical memory regions. When the router attempts to process the corrupted data, it crashes, resulting in a denial-of-service condition.

The vulnerability stems from a flaw in the goform/login handler's processing of HTTP POST data. The router's firmware likely fails to properly validate the size or format of the input data. Specifically, the crafted POST data likely overflows a buffer allocated to store the incoming data. This buffer overflow overwrites critical memory regions, leading to a crash when the router attempts to process the corrupted data. The root cause is a lack of input validation and/or improper memory management within the login processing logic. The specific function or logic flaw is likely related to how the router handles user credentials or session data during the login process. The absence of proper bounds checking on the input data allows an attacker to write beyond the allocated memory space, corrupting the system's state and causing the device to crash.