CVE-2021-20827 : Vulnerability Insights and Analysis

A vulnerability has been identified in IDEC PLCs, specifically in the FC6A Series MICROSmart All-in-One CPU module versions 2.32 and earlier, FC6A Series MICROSmart Plus CPU module versions 1.91 and earlier, WindLDR versions 8.19.1 and earlier, WindEDIT Lite versions 1.3.1 and earlier, and Data File Manager versions 2.12.1 and earlier. This vulnerability allows attackers to access the PLC Web server and potentially hijack the PLC by exploiting plaintext storage of passwords.

Understanding CVE-2021-20827

This section delves into the details of the CVE-2021-20827 vulnerability, its impact, technical aspects, and mitigation strategies.

What is CVE-2021-20827?

The CVE-2021-20827 vulnerability involves plaintext storage of passwords in IDEC PLCs, enabling threat actors to acquire PLC Web server user credentials from various sources like file servers, backup repositories, or ZLD files stored in SD cards. This security weakness may lead to unauthorized access to the PLC Web server, allowing attackers to manipulate the PLC or disrupt its operations.

The Impact of CVE-2021-20827

The impact of CVE-2021-20827 is significant as it permits malicious actors to compromise the integrity and security of IDEC PLCs. By obtaining user credentials, attackers can compromise the PLC Web server, potentially resulting in unauthorized control over the PLC. This unauthorized access could lead to malicious activities such as manipulation of PLC outputs or suspension of PLC operations, posing a serious threat to industrial systems.

Technical Details of CVE-2021-20827

This section provides a deeper insight into the technical aspects of CVE-2021-20827, including vulnerability description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The vulnerability stems from the insecure storage of passwords in IDEC PLCs, specifically affecting the FC6A Series MICROSmart All-in-One CPU module, FC6A Series MICROSmart Plus CPU module, WindLDR, WindEDIT Lite, and Data File Manager. This flaw enables attackers to extract user credentials and compromise the PLC Web server.

Affected Systems and Versions

The affected systems include IDEC PLCs running FC6A Series MICROSmart All-in-One CPU module versions 2.32 and earlier, FC6A Series MICROSmart Plus CPU module versions 1.91 and earlier, WindLDR versions 8.19.1 and earlier, WindEDIT Lite versions 1.3.1 and earlier, and Data File Manager versions 2.12.1 and earlier.

Exploitation Mechanism

Attackers can leverage the plaintext storage of passwords to access user credentials, subsequently infiltrating the PLC Web server. By exploiting this vulnerability, threat actors can gain unauthorized access to the PLC system, potentially leading to severe consequences.

Mitigation and Prevention

In response to CVE-2021-20827, immediate and long-term security measures are essential to safeguard IDEC PLCs from exploitation.

Immediate Steps to Take

Organizations using affected IDEC PLCs should take immediate action to address the vulnerability. This includes updating passwords, implementing network segmentation, and monitoring access logs to detect any suspicious activities.

Long-Term Security Practices

To enhance the security posture of industrial control systems, organizations should prioritize security awareness training, conduct regular security assessments, and enforce strong password policies to mitigate the risk of similar vulnerabilities.

Patching and Updates

It is crucial for users of the affected IDEC PLCs to apply patches and updates provided by IDEC Corporation promptly. Regularly checking for firmware updates, security advisories, and industry best practices can help prevent security breaches and protect critical infrastructure.