CVE-2023-33626 - D-Link DIR-600 Stack Overflow Vulnerability Exploit in Hardware Version B5 and Firmware Version 2.18

Security researchers have discovered a critical vulnerability in D-Link DIR-600 routers (Hardware Version B5 and Firmware Version 2.18) that could potentially compromise the affected devices' ecosystems, exposing them to a range of malicious activities. This vulnerability, tracked as CVE-2023-33626, is a stack overflow build-up in the 'gena.cgi' binary file, ultimately leading to remote code execution and denial of service exploits.

Background

D-Link DIR-600 is a relatively popular router model used widely for its affordability and ease of setup. However, the discovery of this vulnerability could potentially pose a risk to users' home or office networks. A stack overflow occurs when a device or program is erroneously written in a way that allows more data than anticipated to be written into its allocated memory space.

This technical flaw can trigger the 'gena.cgi' binary's overflow, which could further pave the way for unauthorized users to execute malicious code remotely and even crash the affected devices, leading to a denial-of-service attack.

The code snippet below illustrates the vulnerability as observed in the 'gena.cgi' binary

int main(int argc, char **argv);
{
  char buf[512];
  ...
  if (getenv("SUBSCRIBE"))
  {
    strncpy(buf, getenv("SUBSCRIBE"), sizeof(buf)-1);
    ...
  }
  ...
}

In the code snippet above, an HTTP request is used to transmit a subscription to the 'gena.cgi' binary. However, the 'strncpy()' function can be easily exploited to trigger a stack overflow by inputting a long string in the "SUBSCRIBE" value.

Mitigating Measures

D-Link has been notified of this vulnerability, and they have already released an updated firmware version (2.19) addressing this issue. Users with Hardware Version B5 routers running Firmware Version 2.18 are advised to:

1. Immediately upgrade their devices to Firmware Version 2.19. The update can be found on the D-Link support website.

Conclusion

The discovery of this stack overflow vulnerability (CVE-2023-33626) in D-Link DIR-600 routers highlights the importance of having a proactive approach in identifying and addressing security flaws in our devices and networks. By upgrading the firmware and staying vigilant, we can minimize the risks and protect our network's integrity from cyber threats.

Timeline

Published on: 06/12/2023 20:15:00 UTC
Last modified on: 06/16/2023 19:29:00 UTC