This is a proof-of-concept (PoC) and bulk scanner for CVE-2024-29973: Command injection vulnerability in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)

The command injection vulnerability in the “setCookie” parameter in Zyxel NAS326 firmware versions before V5.21(AAZF.17)C0 and NAS542 firmware versions before V5.21(ABAG.14)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted HTTP POST request.

Introduction to Command Injection Vulnerabilities

Command injection vulnerabilities are serious security flaws that allow attackers to execute arbitrary operating system (OS) commands on a vulnerable device. One such vulnerability has been identified in specific firmware versions of Zyxel NAS devices, namely the NAS326 and NAS542 models. This blog post aims to explain this vulnerability, its implications, and the necessary steps to mitigate the risks associated with it.

Details of the Zyxel NAS Vulnerability

In Zyxel NAS326 firmware versions before v5.21(aazf.17)c0 and NAS542 firmware versions before v5.21(abag.14)c0, a command injection vulnerability exists in the ‘setcookie’ parameter. This flaw can be exploited by an unauthenticated attacker who sends a specially crafted HTTP POST request. The vulnerability allows the attacker to execute OS commands on the targeted device, potentially leading to unauthorized access, data theft, or other malicious activities.

Impact and Risks

The command injection vulnerability poses significant risks to affected Zyxel NAS devices. Since the attacker does not need to authenticate, the exploit can be carried out remotely, increasing the attack surface. Successful exploitation can compromise the integrity, confidentiality, and availability of the data stored on these devices. Additionally, compromised devices can be used as entry points for further attacks within the same network.

Mitigation and Recommendations

To protect against this vulnerability, it is crucial to update the firmware of the affected Zyxel NAS devices to the latest versions. Firmware updates v5.21(aazf.17)c0 for NAS326 and v5.21(abag.14)c0 for NAS542 have addressed this security flaw. Regularly checking for and applying firmware updates is a good practice to ensure your devices remain secure. Additionally, network administrators should implement network segmentation and restrict access to NAS devices to minimize potential exposure to attacks.

Conclusion

Staying informed about vulnerabilities and promptly applying security patches are key steps in safeguarding your network and data. The command injection vulnerability in Zyxel NAS devices highlights the importance of regular firmware updates and vigilant security practices. By taking proactive measures, you can significantly reduce the risks posed by such security flaws.