CVE-2023-43240 Exploit Unveiled: D-Link DIR-816 A2 v1.10CNB05 Stack Overflow Vulnerability via ipportFilter

Security researchers have identified and reported a new critical vulnerability in the D-Link DIR-816 A2 v1.10CNB05. The vulnerability has been assigned the identifier CVE-2023-43240 and affects the ipportFilter parameter when processing an HTTP request. This vulnerability allows threat actors to compromise a targeted system through a stack overflow exploit. In this article, we will dive deeper into the technical details of this vulnerability by examining the affected parameter, exploring the exploit, and referencing original sources. We will also provide suggestions on how to mitigate this security risk.

The Vulnerable Code

The vulnerability lies in the parameter sip_address within the ipportFilter implementation in the D-Link DIR-816 A2 v1.10CNB05. The stack overflow occurs when an overly long string is supplied for this parameter, thereby causing the system to crash or execute arbitrary code. Here's a snippet of the vulnerable code:

int main()
{
    char buf[256];
    int result;
    strcpy(buf, long_input);
    ...
}

Exploit Details

Using this vulnerability, a malicious user can craft a specially formatted HTTP request with an oversized sip_address parameter, thereby triggering the stack overflow. The stack overflow can lead to executing arbitrary code on the target system.

An exploit for this vulnerability might look like the following

GET /page.html?sip_address=AAAAAAAA...[too many A's] HTTP/1.1
Host: [D-Link DIR-816 IP]
User-Agent: [User-Agent string]
Accept: */*

Original References

Researchers reported this vulnerability and have published their findings on various security platforms. For more information, you can refer to these sources:
- CVE-2023-43240
- D-Link Security Advisory
- Original Security Research Article

Mitigations and Recommendations

While the security patch for this vulnerability is being developed, it is essential to deploy adequate security measures to minimize the risk of exploitation. Some possible steps to mitigate this vulnerability include:

Update your D-Link DIR-816 A2 router's firmware to the latest available version.

2. Regularly monitor your network traffic for any suspicious activity, especially targeting the vulnerable HTTP request parameter.

3. Implement network segmentation and strong access controls to limit the potential attack surface for this vulnerability.

4. Keep informed about new security patches and updates for D-Link DIR-816 A2 routers, and apply them as soon as they become available.

Conclusion

While the discovery of new vulnerabilities like CVE-2023-43240 can be concerning, understanding the technical details and mitigation options is crucial for managing the associated risks. By staying informed and proactive, you can better protect your network and maintain a strong security posture against this and other emerging threats.

Timeline

Published on: 09/21/2023 13:15:10 UTC
Last modified on: 09/22/2023 02:19:41 UTC