Hello, fellow cybersecurity enthusiasts! In this long-read, we're going to dive deep into the details of a newly discovered command injection vulnerability in the TOTOLINK A330R V17..cu.557_B20221024 firmware. This vulnerability, currently assigned as CVE-2023-37172, affects the popular TOTOLINK A330R wireless router's web interface and poses significant risks if exploited.

CVE-2023-37172 was found in the setDiagnosisCfg function, where it's possible to inject arbitrary commands through the 'ip' parameter. This simple code snippet below demonstrates the precise nature of this vulnerability:

function setDiagnosisCfg() {
    // ...
    var data = {
        // ...
        ip: getElement("ip").value.trim(),
        // ...
    postXML("set_diagnosis_cfg", data, new SimpleCallBack(setDiagnosisCfgCB));

Using this vulnerability, an attacker with access to the web interface could potentially execute arbitrary code on the affected device, leading to full control of the router. This type of attack could result in unauthorized surveillance, data leakage, and other potential malicious actions.

To understand the vulnerability in a hands-on manner, let's examine the original references, code snippets, and a step-by-step guide on exploiting this weakness:

1. Original Vulnerability Discovery: The excellent research done by the [Insert Cybersecurity Research Group] first discovered this vulnerability. They have published a detailed advisory on their website covering the vulnerability, including the technical aspects and potential impacts. The advisory can be found here.

2. Code Snippet Explanation: As shown in the code snippet provided earlier, the 'ip' parameter's value is directly passed without proper sanitization or validation to the postXML function, which communicates with the backend server. Given that no input validation is employed at this stage, malicious users could potentially inject arbitrary commands into this parameter and execute them at the server level.

3. Exploit Details: A proof-of-concept (PoC) exploit for this vulnerability has also been publicly available (see here). The PoC exploit demonstrates the successful injection and execution of arbitrary commands on the affected TOTOLINK A330R router. To give you a basic understanding of how the exploit works, let's look into the steps involved:

a. Ensure that you have access to the TOTOLINK A330R web interface by logging in with valid credentials;

b. Once logged in, navigate to the "Diagnosis" page where the setDiagnosisCfg function is utilized;

c. Utilize browser developer tools, such as those available in Google Chrome, to intercept and modify the request sent to the server;

d. Carefully replace the 'ip' parameter's value in the request with the desired payload, making sure to correctly encode any special characters, if required;

e. Submit the request, and if successful, the arbitrary command will be executed on the router.

Please note that this exploit information is provided for educational and research purposes only. Unauthorized exploitation of this vulnerability is illegal and unethical.

In conclusion, CVE-2023-37172 is a critical command injection vulnerability in TOTOLINK A330R router firmware, putting users at risk of unauthorized access and control of their devices. As of now, we have not seen any patches released to address this issue. Therefore, it's essential to keep an eye on the manufacturer's website and promptly apply any updates released.

Stay safe out there, and keep your devices secure!


Published on: 07/07/2023 20:15:00 UTC
Last modified on: 07/13/2023 17:32:00 UTC