CVE-2021-27426 Explained : Impact and Mitigation

A critical vulnerability has been identified in GE UR family devices, specifically in firmware versions prior to 8.1x. The issue arises from an insecure default variable initialization, potentially allowing unauthorized access to crucial settings. Here's what you need to know about CVE-2021-27426 and how to protect your systems.

Understanding CVE-2021-27426

CVE-2021-27426 refers to a security vulnerability found in GE UR family industrial control system devices due to insecure default variable initialization. The vulnerability exists in firmware versions earlier than 8.1x and can have severe consequences if exploited by malicious actors.

What is CVE-2021-27426?

The vulnerability in GE UR IED firmware versions prior to 8.1x with the 'Basic' security variant prevents the disabling of the 'Factory Mode' feature. This mode is crucial for servicing the IED by a 'Factory' user, posing a significant security risk.

The Impact of CVE-2021-27426

With a CVSS base score of 9.8 and a critical severity rating, CVE-2021-27426 can result in high confidentiality, integrity, and availability impacts. Attackers could potentially exploit this vulnerability through a low-complexity network-based attack vector, necessitating immediate action to mitigate risks.

Technical Details of CVE-2021-27426

Let's delve into more technical aspects of CVE-2021-27426 to understand the vulnerability better.

Vulnerability Description

The vulnerability stems from insecure default variable initialization in GE UR family devices, which prevents the disabling of the 'Factory Mode,' opening avenues for unauthorized manipulation of critical device settings.

Affected Systems and Versions

GE UR IED firmware versions prior to 8.1x with the 'Basic' security variant are impacted by this vulnerability, leaving systems running on these versions susceptible to exploitation.

Exploitation Mechanism

The vulnerability can be exploited by threat actors leveraging a low-complexity attack vector over the network, making it essential to address the issue promptly.

Mitigation and Prevention

Taking immediate actions to remediate CVE-2021-27426 is paramount to safeguard affected systems and prevent potential cyber threats.

Immediate Steps to Take

GE strongly recommends users with impacted firmware versions to update their UR devices to at least UR firmware Version 8.10. Additionally, deploying network defense-in-depth practices and following secure configuration guidelines are crucial measures to enhance system security.

Long-Term Security Practices

In the long term, organizations should adhere to robust security practices, including access controls, monitoring systems, and regular security audits, to mitigate similar vulnerabilities proactively.

Patching and Updates

GE offers UR firmware Version 8.10 or above as a solution to address CVE-2021-27426. Users are also advised to access additional mitigation details provided in GE Publication Number GES-2021-004 for comprehensive protection.