Source: cve@mitre.org
The TK_set_deviceModel_req_handle function in the cloud communication component in Guardzilla GZ621W devices with firmware 0.5.1.4 has a Buffer Overflow.
Guardzilla GZ621W devices running firmware 0.5.1.4 are vulnerable to a buffer overflow in the cloud communication component, potentially allowing for remote code execution. Successful exploitation could lead to complete device compromise, enabling attackers to gain unauthorized access to video feeds, network credentials, and other sensitive information. This vulnerability poses a significant risk to home and small business users.
Step 1: Trigger Request: The attacker sends a specially crafted network request to the Guardzilla GZ621W device, targeting the cloud communication component. This request likely contains a device model string that is longer than the allocated buffer within the TK_set_deviceModel_req_handle function.
Step 2: Function Invocation: The malicious request triggers the execution of the TK_set_deviceModel_req_handle function.
Step 3: Buffer Overflow: The function attempts to copy the oversized device model string into the fixed-size buffer. Due to the lack of bounds checking, the copy operation overflows the buffer, overwriting adjacent memory locations.
Step 4: Code Injection/Control: The attacker's crafted input overwrites critical program data, such as function pointers or return addresses. This allows the attacker to redirect program execution to a location of their choosing, such as a shellcode payload injected into the overflowed buffer.
Step 5: Shellcode Execution (Optional): If the attacker successfully injects and executes shellcode, they gain control of the device, potentially allowing them to execute arbitrary commands, access sensitive data (video feeds, credentials), and establish persistent access.
The vulnerability lies within the TK_set_deviceModel_req_handle function of the cloud communication component. This function is responsible for handling requests related to the device model. The root cause is a buffer overflow due to insufficient bounds checking when processing the device model string. Specifically, the function allocates a fixed-size buffer to store the model string received from an external source (likely a network request). If the received model string exceeds the buffer's capacity, it overwrites adjacent memory regions, potentially overwriting critical program data or control flow instructions. This allows an attacker to control the program's execution by injecting malicious code into the overwritten memory. The lack of input validation and the use of a fixed-size buffer are the primary contributing factors to this vulnerability. The function likely uses strcpy or a similar function without proper bounds checking, leading to the overflow.
While no specific APT groups are directly linked, the nature of the vulnerability makes it attractive to attackers seeking to compromise IoT devices. The potential for remote access and data exfiltration makes this a valuable target. Not listed on CISA KEV.
Network traffic analysis: Monitor for unusually large requests to the cloud communication component, specifically those containing excessively long device model strings.
IDS/IPS signatures: Implement signatures to detect the specific pattern of the malicious device model string.
Log analysis: Examine device logs for errors or unusual activity related to the cloud communication component, such as segmentation faults or unexpected program behavior.
Firmware analysis: Analyze the firmware image for the vulnerable function and the presence of the buffer overflow vulnerability.
Upgrade Firmware: Update the Guardzilla GZ621W device to a patched firmware version (if available).
Input Validation: Implement robust input validation to ensure that the device model string does not exceed the allocated buffer size.
Memory Safety: Employ memory safety techniques, such as using safer string handling functions (e.g., strncpy) or using a memory-safe programming language.
Network Segmentation: Isolate the Guardzilla devices on a separate network segment to limit the impact of a potential compromise.
Regular Security Audits: Conduct regular security audits and penetration tests to identify and address vulnerabilities.