CVE-2020-27632: High severity siemens simatic mv420 vulnerability

Published Mar 10, 2021
·
Updated

In SIMATIC MV400 family versions prior to v7.0.6, the ISN generator is initialized with a constant value and has constant increments. An attacker could predict and hijack TCP sessions.

Affected Software

17 affected components
Siemens Simatic Mv420 Firmware<7.0.6
Siemens Simatic Mv420
Siemens Simatic Mv440 Firmware<7.0.6
Siemens Simatic Mv440
Multiple Nut/Net, Version 5.1 and prior
Multiple CycloneTCP, Version 1.9.6 and prior
Multiple NDKTCPIP, Version 2.25 and prior
Multiple FNET, Version 4.6.3
Multiple uIP-Contiki-OS (end-of-life [EOL]), Version 3.0 and prior
Multiple uC/TCP-IP (EOL), Version 3.6.0 and prior
Multiple uIP-Contiki-NG, Version 4.5 and prior
Multiple uIP (EOL), Version 1.0 and prior
Multiple picoTCP-NG, Version 1.7.0 and prior
Multiple picoTCP (EOL), Version 1.7.0 and prior
Multiple MPLAB Net, Version 3.6.1 and prior
Multiple Nucleus NET, All versions prior to Version 5.2
Multiple Nucleus ReadyStart for ARM, MIPS, and PPC, All versions prior to Version 2012.12

Event History

Mar 10, 2021
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
Description

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is CVE-2020-27632?

CVE-2020-27632 is a vulnerability in SIMATIC MV400 family versions prior to v7.0.6 where the ISN generator is initialized with a constant value and has constant increments, allowing an attacker to predict and hijack TCP sessions.

2

Which software versions are affected by CVE-2020-27632?

SIMATIC MV400 family versions prior to v7.0.6 are affected by CVE-2020-27632.

3

How severe is CVE-2020-27632?

CVE-2020-27632 has a severity rating of 7.5 (high).

4

How can I fix CVE-2020-27632?

To fix CVE-2020-27632, it is recommended to update the affected SIMATIC MV400 family device to version v7.0.6 or later.

5

Where can I find more information about CVE-2020-27632?

You can find more information about CVE-2020-27632 at the following references: [Siemens CERT Portal](https://cert-portal.siemens.com/productcert/pdf/ssa-599268.pdf), [CISA ICS Advisories](https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01), [Forescout - Numberjack Weak ISN Generation in Embedded TCP/IP Stacks](https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/).

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