CVE-2018-7856 Explained : Impact and Mitigation

The Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium are vulnerable to a CWE-248: Uncaught Exception issue, potentially leading to a denial of service if invalid memory blocks are written to the controller via Modbus.

Understanding CVE-2018-7856

This CVE involves multiple vulnerabilities in Schneider Electric's Modicon series.

What is CVE-2018-7856?

A CWE-248: Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium, posing a risk of denial of service when writing invalid memory blocks to the controller over Modbus.

The Impact of CVE-2018-7856

The vulnerability could allow attackers to disrupt operations by writing invalid memory blocks to the controller.
This could potentially lead to a denial of service situation, impacting the availability of the affected systems.

Technical Details of CVE-2018-7856

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability is categorized as a CWE-248: Uncaught Exception issue, which can be exploited to disrupt the affected systems.

Affected Systems and Versions

Products affected: Modicon M580, Modicon M340, Modicon Quantum, Modicon Premium
Vulnerable versions: Modicon M580, Modicon M340, Modicon Quantum, Modicon Premium

Exploitation Mechanism

The vulnerability can be exploited by writing invalid memory blocks to the controller via Modbus, potentially causing a denial of service.

Mitigation and Prevention

Protecting systems from CVE-2018-7856 is crucial to maintaining security.

Immediate Steps to Take

Apply security patches provided by Schneider Electric promptly.
Implement network segmentation to limit the impact of potential attacks.
Monitor network traffic for any suspicious activities.

Long-Term Security Practices

Regularly update and patch all software and firmware to address known vulnerabilities.
Conduct security assessments and penetration testing to identify and remediate weaknesses.

Patching and Updates

Stay informed about security advisories and updates from Schneider Electric.
Ensure that all devices are running the latest firmware and software versions to mitigate the risk of exploitation.