CVE-2024-0535: Critical Buffer Overflow in Tenda PA6 1.0.1.21

Overview

In this blog post, we delve into the intricacies of a critical vulnerability found in Tenda PA6 1.0.1.21, identified as CVE-2024-0535. This vulnerability, with a CVSS Severity Score of 8.8, is notable as it can potentially lead to a full system compromise or data leakage. We will discuss the vulnerability in detail, its potential risks, and how to mitigate it.

Vulnerability Summary

CVE-2024-0535 is a stack-based buffer overflow vulnerability affecting the `cgiPortMapAdd` function of the `/portmap` file in the Tenda PA6’s `httpd` component. The manipulation of the `groupName` argument is the root cause of this vulnerability. The exploit can be launched remotely, and the details have been made public, adding urgency to the need for a robust solution. The identifier VDB-250705 was assigned to this vulnerability.

It’s important to note that the vendor was contacted regarding this disclosure but did not respond, which means the official patch might not be available yet.

How the Exploit Works

The exploit works by manipulating the `groupName` argument in the `cgiPortMapAdd` function. By sending an overly long string to this argument, an attacker can trigger a buffer overflow. This overflow can corrupt the stack, enabling the attacker to execute arbitrary code or cause a Denial of Service (DoS) condition.

Conceptual Example Code

Although the specific code for this exploit is beyond the scope of this blog post, conceptual examples of the exploit can be found in these links:

– [Example 1](https://github.com/jylsec/vuldb/blob/main/Tenda/PA6/2/README.md)
– [Example 2](https://github.com/jylsec/vuldb/blob/main/Tenda/PA6/2/README.md)

Please use these resources responsibly, they are intended for education and awareness purposes only.

Potential Risks

The potential risks associated with this vulnerability are severe. Given that the exploit can be launched remotely and the details are public, this leaves systems running on Tenda PA6 1.0.1.21 extremely vulnerable. The risks include:

– Unauthorized system access: Attackers can exploit this vulnerability to gain unauthorized access to the system.
– Data leakage: Once the system is compromised, attackers may access and leak sensitive data.
– System instability: The exploit can cause system crashes, leading to potential downtime.

Mitigation Recommendations

Although the vendor has yet to release an official patch, there are interim solutions that can mitigate the vulnerability:

– Apply a Web Application Firewall (WAF) or Intrusion Detection System (IDS): These tools can help detect and prevent suspicious activities, including buffer overflow attacks.
– Regularly update and patch your systems: Always ensure your systems are up-to-date with the latest security patches.
– Monitor your systems: Regularly monitor your systems for any suspicious activities. Early detection can help prevent potential security breaches.

Conclusion

In conclusion, CVE-2024-0535 is a critical vulnerability that can lead to system compromise or data leakage. As cybersecurity professionals, it’s crucial to stay vigilant and proactive in managing such vulnerabilities. By applying the recommended mitigations and continuously monitoring your systems, you can better protect your systems from potential threats. Stay tuned for more updates on this and other cybersecurity topics.