CVE-2021-21739 : Exploit Details and Defense Strategies

A security vulnerability has been discovered in ZTE's product of the transport network access layer, CVE-2021-21739 allows attackers to bypass system authentication and detection by replacing an authenticated optical module with an unauthenticated one on the affected equipment.

Understanding CVE-2021-21739

This CVE describes an insufficient verification of data reliability vulnerability in ZTE's product ZXCTN 6120H (version V5.10.00B24).

What is CVE-2021-21739?

CVE-2021-21739 is a security vulnerability in ZTE's transport network access layer product, allowing malicious actors to compromise signal transmission by circumventing system authentication.

The Impact of CVE-2021-21739

The security flaw in ZXCTN 6120H (version V5.10.00B24) can result in unauthorized replacement of optical modules, leading to potential signal transmission disruption.

Technical Details of CVE-2021-21739

This section provides further insight into the vulnerability.

Vulnerability Description

The vulnerability arises due to inadequate data reliability verification, enabling attackers to subvert system authentication and detection mechanisms.

Affected Systems and Versions

Affected Product: ZXCTN 6120H
Affected Version: V5.10.00B24

Exploitation Mechanism

Attackers exploit the vulnerability by replacing an authenticated optical module with an unauthenticated one on the targeted equipment, impacting signal transmission.

Mitigation and Prevention

To secure systems against CVE-2021-21739, follow these steps:

Immediate Steps to Take

Implement strict access controls and authentication mechanisms.
Monitor all equipment for unauthorized changes.

Long-Term Security Practices

Regularly update and patch systems to mitigate known vulnerabilities.
Conduct security training for employees to raise awareness of potential threats.

Patching and Updates

Stay informed about security advisories and apply patches provided by ZTE to address the vulnerability.