CVE-2021-27342 : Vulnerability Insights and Analysis

This article provides details about CVE-2021-27342, a vulnerability that affects D-Link Router model DIR-842 firmware version 3.0.2, allowing remote attackers to bypass authentication brute-force protection mechanisms.

Understanding CVE-2021-27342

This section delves into the impact and technical details of the CVE-2021-27342 vulnerability.

What is CVE-2021-27342?

CVE-2021-27342 is an authentication brute-force protection mechanism bypass vulnerability in telnetd in D-Link Router model DIR-842 firmware version 3.0.2. It enables remote attackers to evade the anti-brute-force cool-down delay period through a timing-based side-channel attack.

The Impact of CVE-2021-27342

The vulnerability allows malicious actors to carry out brute-force attacks efficiently, which can lead to unauthorized access to affected devices and potential compromise of sensitive information.

Technical Details of CVE-2021-27342

This section provides insight into the vulnerability, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The flaw in telnetd in D-Link Router model DIR-842 firmware version 3.0.2 permits remote attackers to circumvent the anti-brute-force cool-down delay period, enhancing the success rate of unauthorized access attempts.

Affected Systems and Versions

D-Link Router model DIR-842 firmware version 3.0.2 is confirmed to be impacted by this vulnerability.

Exploitation Mechanism

Remote attackers exploit a timing-based side-channel attack to bypass the authentication brute-force protection mechanism and gain unauthorized access to the affected router.

Mitigation and Prevention

In this section, we explore the steps to mitigate the risks posed by CVE-2021-27342 and prevent potential security breaches.

Immediate Steps to Take

Users are advised to update the D-Link Router model DIR-842 firmware to a secure version that addresses the authentication bypass vulnerability. Additionally, network administrators can monitor network traffic for any suspicious activity.

Long-Term Security Practices

Implementing strong, unique passwords, enabling multi-factor authentication, and regularly updating firmware are crucial long-term security measures to protect against brute-force attacks and other vulnerabilities.

Patching and Updates

D-Link has released patches to address CVE-2021-27342. It is essential for users to promptly apply these updates to ensure the security of their devices and networks.