CVE-2018-7843 Denial of service in Modicon M580 Modicon M340 Modicon Quantum Modicon Premium

High 7.5 Published 22 May 2019 Updated 5 Aug 2024

Attackers can cause denial of service on Modicon PLCs by sending malformed Modbus requests with invalid data sizes or offsets.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2018-7843?

CVE-2018-7843 is a high-severity denial of service vulnerability in Modicon M580 Modicon M340 Modicon Quantum Modicon Premium, published on 22 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A CWE-248: Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause denial of service when reading memory blocks with an invalid data size or with an invalid data offset in the controller over Modbus.

Weakness: CWE-125

Which versions are affected by CVE-2018-7843?

It affects 4 products.

Products include Schneider-Electric Modicon M340 Firmware, Schneider-Electric Modicon M580 Firmware, Schneider-Electric Modicon Premium Firmware, Schneider-Electric Modicon Quantum Firmware.

How do I fix CVE-2018-7843?

No fix has been published for CVE-2018-7843 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-7843 being exploited?

There is no known exploitation of CVE-2018-7843 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as GHSA-48rw-r4xr-j8j2.