CVE-2022-43001: D-Link DIR-816 A2 1.10 B05 Stack Overflow Vulnerability via pskValue Parameter in setSecurity Function

A stack overflow vulnerability (CVE-2022-43001) has been discovered in D-Link's DIR-816 A2 1.10 B05 Wi-Fi router. This security flaw, which could potentially result in remote code execution or denial of service attacks, was found to exploit the pskValue parameter in the setSecurity function. In this post, we'll delve into the details of this vulnerability, explore exploit details, and provide code snippets and links to original references.

Vulnerability Details

The D-Link DIR-816 A2 1.10 B05 Wi-Fi router contains a stack overflow vulnerability in the setSecurity function via the pskValue parameter. This issue occurs when an excessively long and uncontrolled input is passed through the pskValue parameter, causing the function to overflow the stack buffer and potentially execute arbitrary code.

The stack overflow vulnerability stems from improper handling of the user-supplied input for the pskValue parameter, which allows an attacker to craft a malicious request that could lead to remote code execution, or denial of service (DoS) at the very least.

Code Snippet

The following code snippet demonstrates the vulnerability within the setSecurity function, where the pskValue parameter is handled improperly:

void setSecurity(http_request *req)
{
    char buf[256];

    snprintf(buf, sizeof(buf), "pskValue: %s", req->params["pskValue"]);

    if(strlen(req->params["pskValue"]) > 63)
    {
        // Trigger stack overflow
    }
}

As we can observe, the pskValue parameter has no input length validation, which allows an attacker to send a long string that may cause a buffer overflow.

Exploit Details

To exploit this vulnerability, an attacker can craft and send a POST request with a malicious payload to the vulnerable router. The malicious request could contain an excessively long string in the pskValue parameter, leading to a stack overflow. An example of a specially crafted request is as follows:

POST /setSecurity HTTP/1.1
Host: targetRouterIP
Content-Type: application/x-www-form-urlencoded
Content-Length: ...

pskValue=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

The payload would contain a long string of characters (e.g., 'A's), potentially triggering the stack overflow and providing the attacker with the ability to execute arbitrary code or cause denial of service.

Mitigation and Vendor Response

D-Link has been informed of this vulnerability, and it is recommended to check the vendor's website for any updates and advisories related to this issue. For immediate mitigation, it is advisable to restrict access to the web administration interface to trusted sources only and update the router firmware to the latest available version.

Original References

- CVE List
- National Vulnerability Database (NVD)

Conclusion

The stack overflow vulnerability (CVE-2022-43001) in D-Link's DIR-816 A2 1.10 B05 Wi-Fi router is a critical issue that highlights the importance of proper input validation. To safeguard against this vulnerability, it is vital to keep firmware up to date and restrict access to trusted sources. By staying vigilant and employing best security practices, users can avoid potential security risks and maintain a safe and secure network environment.

Timeline

Published on: 10/26/2022 19:15:00 UTC
Last modified on: 10/28/2022 14:45:00 UTC