CVE-2018-7851 Explained : Impact and Mitigation

A vulnerability related to buffer errors affects various Schneider Electric devices, potentially leading to denial of service when receiving specially crafted Modbus packets.

Understanding CVE-2018-7851

This CVE identifies a specific vulnerability in Schneider Electric devices that could be exploited to disrupt their operation.

What is CVE-2018-7851?

The vulnerability, known as CWE-119, impacts Modicon M580, Modicon M340, BMxCRA312xx, Modicon Premium, and 140CRA312xxx devices with specific firmware versions.

The Impact of CVE-2018-7851

Exploiting this vulnerability could result in a denial of service, requiring affected devices to be restarted to resume normal functionality.

Technical Details of CVE-2018-7851

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability is related to buffer errors and is triggered by sending specially designed Modbus packets to the affected Schneider Electric devices.

Affected Systems and Versions

Modicon M580 with firmware prior to V2.50
Modicon M340 with firmware prior to V3.01
BMxCRA312xx with firmware prior to V2.40
All firmware versions of Modicon Premium and 140CRA312xxx

Exploitation Mechanism

Sending a crafted Modbus packet to the vulnerable devices can lead to a denial of service, necessitating a device restart for recovery.

Mitigation and Prevention

Protecting systems from this vulnerability requires specific actions.

Immediate Steps to Take

Apply patches or updates provided by Schneider Electric promptly.
Implement network segmentation to isolate vulnerable devices.
Monitor network traffic for any suspicious activity targeting these devices.

Long-Term Security Practices

Regularly update firmware to the latest versions to mitigate known vulnerabilities.
Conduct security assessments and penetration testing to identify and address potential weaknesses.

Patching and Updates

Stay informed about security advisories from Schneider Electric.
Follow best practices for secure device configuration and network architecture.