CVE-2022-43391 Explained : Impact and Mitigation

This article provides detailed information about CVE-2022-43391, a buffer overflow vulnerability in Zyxel NR7101 firmware prior to V1.15(ACCC.3)C0 that could lead to denial-of-service conditions when exploited by an authenticated attacker.

Understanding CVE-2022-43391

CVE-2022-43391 is a vulnerability in Zyxel NR7101 firmware that allows an attacker to trigger denial-of-service conditions by exploiting a buffer overflow issue in the CGI program.

What is CVE-2022-43391?

The CVE-2022-43391 vulnerability exists in the parameter of the CGI program within Zyxel NR7101 firmware versions prior to V1.15(ACCC.3)C0. It can be exploited by an authenticated attacker to generate denial-of-service conditions by sending a specifically crafted HTTP request.

The Impact of CVE-2022-43391

This vulnerability could result in denial-of-service conditions, disrupting the normal operation of affected Zyxel NR7101 devices. An attacker could exploit this weakness to render the device unresponsive, impacting its availability.

Technical Details of CVE-2022-43391

CVE-2022-43391 has a CVSSv3.1 base score of 6.5, indicating a medium severity vulnerability with a low attack complexity and network vector. The availability impact is high, requiring low privileges for exploitation with no user interaction necessary.

Vulnerability Description

The vulnerability is classified as CWE-120, indicating a buffer overflow issue in the CGI program that allows an attacker to cause denial-of-service conditions on the affected Zyxel NR7101 firmware.

Affected Systems and Versions

Zyxel NR7101 firmware versions below V1.15(ACCC.3)C0 are impacted by this vulnerability.

Exploitation Mechanism

An authenticated attacker can trigger the buffer overflow vulnerability by sending a malicious HTTP request to the CGI program in the affected Zyxel NR7101 firmware.

Mitigation and Prevention

To address CVE-2022-43391, immediate steps should be taken to enhance the security posture of affected Zyxel NR7101 devices and prevent potential exploitation.

Immediate Steps to Take

It is recommended to update Zyxel NR7101 firmware to version V1.15(ACCC.3)C0 or newer to mitigate the vulnerability. Additionally, network security measures should be enforced to restrict access to sensitive resources.

Long-Term Security Practices

Regular security assessments and code reviews can help identify and remediate similar vulnerabilities in the future. Security awareness training for users can also aid in preventing successful exploitation of known vulnerabilities.

Patching and Updates

Stay informed about security advisories from Zyxel and apply patches promptly to secure your systems from potential threats and vulnerabilities.