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A recent vulnerability, identified as CVE-2024-12856, has been discovered in the Four-Faith router models F3x24 and F3x36. This security issue enables both authenticated and remote attackers to execute arbitrary Operating System (OS) commands through an OS command injection vulnerability. This article will provide details on this dangerous exploit, how it works, and how it can be mitigated. We will also provide a link to the original references and the code snippet responsible for the vulnerability.

Exploit Details

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Affected Four-Faith router models (F3x24 and F3x36) are susceptible to an OS command injection vulnerability due to insufficient user input validation mechanisms in the router's firmware. At least firmware version 2. is affected by this vulnerability.

This security loophole can be exploited by authenticated, remote attackers to execute arbitrary OS commands on the router's underlying operating system. The vulnerability is triggered when modifying the system time via apply.cgi. The exploit leverages the HTTP protocol for interaction and transmission of commands.

Worse still, the affected firmware version (2.) includes default credentials. If unchanged, the vulnerability effectively becomes an unauthenticated, remote OS command execution problem – leaving the affected routers wide open to potential attacks and unauthorized access.

Code Snippet

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The vulnerable section of code is found in the apply.cgi file, where the input provided to change the system time is not properly sanitized, allowing the attacker to inject and execute OS commands.

/* ... */
char cmd[128] = {};
/* ... */
snprintf(cmd, sizeof(cmd), "date -s '%s'", user_input);
/* ... */
system(cmd);
/* ... */

By injecting malicious OS commands via the user_input variable, the attacker is able to force the router's OS to execute those commands, leading to potential unauthorized access and router compromise.

Original References

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- CVE Details
- Exploit Database Entry
- Router Vendor - Four-Faith

Mitigation

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To mitigate this vulnerability, owners of affected Four-Faith routers (F3x24 and F3x36 models running at least firmware version 2.) should take the following steps:

1. Update the router's firmware to the latest security-patched version – consult your router manual or contact vendor support for assistance.
2. Change the default router login credentials to secure, unique credentials that cannot be easily guessed or discovered.
3. Review and restrict remote access settings – only enabling remote access when necessary, and limit to trusted, authorized users.

Conclusion

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CVE-2024-12856 is a significant vulnerability affecting Four-Faith router models F3x24 and F3x36. If left unpatched and unmitigated, attackers can remotely exploit and compromise routers leading to unauthorized access and potential harm. Affected users are urged to follow the mitigation steps outlined above and keep their router firmware updated to the latest, most secure version.

Timeline

Published on: 12/27/2024 16:15:23 UTC
Last modified on: 12/27/2024 18:15:23 UTC