CVE-2021-20609 : Exploit Details and Defense Strategies

A vulnerability in Mitsubishi Electric MELSEC series CPUs could allow a remote attacker to trigger a denial-of-service condition through specially crafted packets.

Understanding CVE-2021-20609

This CVE involves an Uncontrolled Resource Consumption vulnerability affecting various Mitsubishi Electric MELSEC series CPUs.

What is CVE-2021-20609?

The CVE-2021-20609 vulnerability in Mitsubishi Electric MELSEC series CPUs permits remote unauthenticated attackers to induce a denial-of-service (DoS) state by sending manipulated packets, necessitating a system reset for recovery.

The Impact of CVE-2021-20609

The primary impact of this vulnerability is a Denial of Service (DoS) condition, potentially disrupting operations until the affected system is reset.

Technical Details of CVE-2021-20609

This section covers specific technical aspects of the vulnerability.

Vulnerability Description

The Uncontrolled Resource Consumption flaw affects various Mitsubishi Electric MELSEC CPUs, enabling attackers to disrupt services by sending crafted packets.

Affected Systems and Versions

Multiple MELSEC series CPUs are impacted, including MELSEC iQ-R, MELSEC Q Series, MELSEC L Series, and MELIPC Series.

Exploitation Mechanism

The vulnerability can be exploited remotely by sending specially crafted packets to the affected CPUs, causing a denial-of-service condition.

Mitigation and Prevention

Here are the steps to mitigate the CVE-2021-20609 vulnerability.

Immediate Steps to Take

Apply patches or updates provided by Mitsubishi Electric Corporation.
Monitor network traffic for any signs of exploitation.

Long-Term Security Practices

Implement network segmentation to isolate critical systems.
Regularly update and patch all industrial control system components.

Patching and Updates

Ensure that the firmware or operating system software of the affected Mitsubishi Electric MELSEC CPUs is updated to versions that address the CVE-2021-20609 vulnerability.