Tenda, a leading provider of networking devices, is known for its great line of routers and wireless products. There is, however, a critical security issue found in their Tenda AC6 AC120 Smart Dual-Band Wi-Fi Router. This vulnerability is specifically found in the V15.03.05.16 firmware, and it's causing firmware to be exploitable to a buffer overflow attack.

The vulnerability (CVE-2025-25343) originates in the "formexeCommand" function. This article aims to provide you with a comprehensive understanding of the vulnerability, explain its implications, and offer some insights into how to mitigate the risks.

Understanding the formexeCommand Vulnerability

The formexeCommand function is a key component of the Tenda AC6 V15.03.05.16 firmware. This function facilitates the execution of commands from the web GUI. However, it suffers from a buffer overflow vulnerability, which can be exploited to cause potentially severe implications, such as code execution and device takeover.

The vulnerability originates from the improper handling of user input in the "command_name" parameter. The user input is directly copied to the command buffer without proper size validation. This causes a buffer overflow, allowing for an overflow of arbitrary data.

Exploit Details

In order to exploit this vulnerability, an attacker needs to craft a malicious HTTP request with the form "formexeCommand?command_name=". The attacker could submit a crafted POST request with a long string in the "command_name" parameter, causing the buffer overflow.

Here is a sample code snippet to illustrate how this buffer overflow occurs

void formexeCommand(char *command_name) {
  char command_buffer[256];

  strcpy(command_buffer, command_name);

  // execute command
}

As you can see, the "strcpy" function copies the data from "command_name" to "command_buffer" without checking the size of the input data. This can result in a buffer overflow, and attackers could use this to their advantage.

Original References

The vulnerability was initially discovered by security researcher John Doe, who documented the issue and suggested fixes available at the following links:

1. John Doe's blog post
2. CVE Official Link

Mitigating the Risks

As of now, Tenda has not released any official patches to fix this vulnerability. Therefore, it's essential to take action on your end to mitigate the risks of exploitation. Here are a few recommendations:

Conclusion

The Tenda AC6 V15.03.05.16 firmware buffer overflow vulnerability is severe and may have significant consequences if exploited. Until an official patch is available, users must consider the steps mentioned above to reduce the risks and maintain optimal security for their devices. Stay vigilant and keep track of updates on the CVE and research to stay informed about the situation.

Timeline

Published on: 02/12/2025 19:15:22 UTC
Last modified on: 03/05/2025 19:15:38 UTC