CVE-2021-20599 : Exploit Details and Defense Strategies

A detailed guide on CVE-2021-20599, covering its description, impact, technical details, mitigation, and prevention methods.

Understanding CVE-2021-20599

CVE-2021-20599 involves a cleartext transmission vulnerability in Mitsubishi Electric MELSEC iQ-R series Safety CPU and SIL2 Process CPU firmware versions that could allow a remote attacker to login to a target CPU module.

What is CVE-2021-20599?

The vulnerability in the mentioned Mitsubishi Electric products enables an unauthenticated remote attacker to access a CPU module by obtaining credentials other than the password.

The Impact of CVE-2021-20599

This vulnerability poses a significant threat as it allows unauthorized access to critical systems, leading to potential data breaches, unauthorized control, and system compromise.

Technical Details of CVE-2021-20599

Here are the technical details of CVE-2021-20599:

Vulnerability Description

The issue lies in the cleartext transmission of sensitive information, making it easier for attackers to intercept and misuse data transmitted between the target CPU module and other systems.

Affected Systems and Versions

Vendor: Mitsubishi Electric
Affected Products:
MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU
MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU
Affected Versions:
Mitsubishi Electric MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU Firmware versions "26" and prior
Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU All versions

Exploitation Mechanism

The vulnerability can be exploited remotely by a threat actor without the need for authentication, potentially leading to unauthorized access to critical systems and sensitive information.

Mitigation and Prevention

To address CVE-2021-20599, consider the following steps:

Immediate Steps to Take

Monitor vendor communications for security advisories and updates
Implement network segmentation to limit exposure
Change default credentials and use strong passwords

Long-Term Security Practices

Conduct regular security assessments and penetration testing
Implement encryption for sensitive data transmission
Train employees on cybersecurity best practices

Patching and Updates

Apply security patches and firmware updates provided by Mitsubishi Electric
Keep systems up to date with the latest security configurations and recommendations