CVE-2022-44202: D-Link DIR878 (1.02B04 & 1.02B05) Vulnerable to Buffer Overflow Attack - Exploit Details, Code Snippets, and Mitigation

The purpose of this post is to discuss the recently discovered vulnerability in D-Link DIR878 routers, specifically models running firmware versions 1.02B04 and 1.02B05. This vulnerability, registered under CVE-2022-44202, could allow an attacker to remotely execute malicious code on an affected router, leading to unauthorized access and potentially compromising the security of your home or office network.

In this post, we will dive into the technical details of this vulnerability, including the buffer overflow attack, the vulnerable code snippet, and the exploit details. Additionally, we will provide links to the original references and advisories related to this vulnerability, as well as discuss some possible mitigation strategies for affected users.

Vulnerable Code Snippet

The vulnerability exists in a specific function within the router's firmware, which fails to properly handle user input, leading to a buffer overflow. A buffer overflow occurs when an application writes more data to a buffer than it can hold, causing the excess data to overflow into adjacent memory locations. In this case, the overflow allows an attacker to overwrite critical memory locations and execute arbitrary code on the router, without requiring authentication.

Here is a simplified, pseudo-code version of the vulnerable function

int vulnerable_function (char *user_input) {
  char buffer[64];
  strcpy(buffer, user_input);
  // ... other code ...
}

In this example, the function uses strcpy() to copy user input into a fixed-size buffer without checking the size of the input. This could allow an attacker to craft a malicious input that is larger than the buffer can hold, resulting in a buffer overflow.

Identify a target router running firmware version 1.02B04 or 1.02B05.

2. Craft a malicious payload that is larger than the target buffer (64 bytes), and includes arbitrary code to be executed on the target router.

Send the payload to the target router, triggering the buffer overflow vulnerability.

4. Once the buffer overflow occurs, the arbitrary code included in the payload will be executed on the target router, allowing the attacker to gain unauthorized access and control.

Original References

Link to CVE entry: CVE-2022-44202
Link to D-Link Security Advisory: D-Link DIR-878 Router Buffer Overflow

Mitigation

To protect your network against this vulnerability, D-Link has released updated firmware versions for the affected routers. It is highly recommended that you upgrade your router's firmware to the latest version as soon as possible. You can find the firmware downloads and installation instructions on the D-Link support site:

- DIR-878 Firmware 1.20WW (Global)
- DIR-878 Firmware 1.20B03 (USA)

If you cannot update your router's firmware immediately, consider the following temporary measures to reduce the risk of exploitation:

Conclusion

D-Link router models DIR878 running firmware versions 1.02B04 and 1.02B05 are vulnerable to a buffer overflow attack, as described in CVE-2022-44202. The vulnerable code snippet and exploit details provided in this post demonstrate the potential impact of this vulnerability on your network security. To mitigate the risk, update your router's firmware as soon as possible and consider implementing additional security measures such as restricting remote access to the router.

Remember, keeping your devices and software up-to-date is an essential part of protecting your network and ensuring the security of your data. In this case, a simple firmware update can significantly reduce the risk posed by this vulnerability.

Timeline

Published on: 11/22/2022 15:15:00 UTC
Last modified on: 11/23/2022 19:53:00 UTC