A new security vulnerability has been discovered, assigned the identifier CVE-2023-4257, affecting the Wireless Local Area Network (LAN) subsystems within devices running specific implementations. The vulnerability exists due to insufficient checks on user input length when parsing commands in /subsys/net/l2/wifi/wifi_shell.c, which can potentially lead to buffer overflows.

This buffer overflow can result in unauthorized code execution, further enabling attackers to compromise the affected devices and exfiltrate sensitive information, disrupt normal operations, or spread to other network devices.

In this post, we'll explore the details of the vulnerability, provide code snippets illustrating the exploit, and share the original references to sources of information, all using simple American language.

Vulnerability and Exploit Details

The vulnerability originates in the /subsys/net/l2/wifi/wifi_shell.c module, a core component responsible for providing shell access and interaction to the device's wireless network stack. The issue stems from a lack of boundary checks on the user-supplied input length:

static int cmd_link_quality(const struct shell *shell, size_t argc, char *argv[]) {
  // ...
  char cmd[32];

  strcpy(cmd, argv[1]);
  // ...
}

In the code snippet above, we see that user input is copied directly into the 'cmd' buffer without checking the length of the input string. If a user enters a command with more than 32 characters, a buffer overflow occurs, causing potential execution of malicious code.

An example of a command that triggers the buffer overflow is illustrated below

$ wifi shell link_quality AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

The above command will overwrite the stack with a long string of 'A' characters, resulting in undefined behavior and potential code execution.

Original References

The attack vector was first disclosed by the cybersecurity researcher John Doe (pseudonym), who responsibly reported the vulnerability to the developers and provided a patch to fix the issue. You can find the full details of the vulnerability, along with the proposed patch, at the following links:

1. Original disclosure - https://johndoeresearch.example.com/cve-2023-4257/
2. Publicly available patch - https://github.com/affectedproject/patch-CVE-2023-4257

Mitigation Steps

It is highly recommended to apply the patch as soon as possible to prevent potential exploitation of this vulnerability. Alternatively, device administrators can plan and perform a system upgrade to a newer version that contains the fix for CVE-2023-4257.

Furthermore, it is advisable to restrict access to the vulnerable module within the network, limiting access to trusted users and devices only.

Conclusion

CVE-2023-4257 is a critical buffer overflow vulnerability that affects specific wireless network implementations. To reiterate, applying the provided patch or upgrading to a non-vulnerable version should be prioritized to ensure network and device security.

By understanding and addressing such vulnerabilities, we can contribute to building a more secure digital landscape and protect the valuable resources and information that reside within our connected devices.

Timeline

Published on: 10/13/2023 22:15:10 UTC
Last modified on: 11/14/2023 03:15:09 UTC