CVE-2020-27632
First published: Wed 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.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| 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 |
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Reference Links
Frequently Asked Questions
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.
Which software versions are affected by CVE-2020-27632?
SIMATIC MV400 family versions prior to v7.0.6 are affected by CVE-2020-27632.
How severe is CVE-2020-27632?
CVE-2020-27632 has a severity rating of 7.5 (high).
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.
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/).
- collector/nvd-api
- collector/nvd-index
- agent/author
- agent/type
- agent/last-modified-date
- agent/first-publish-date
- agent/severity
- agent/weakness
- agent/references
- agent/softwarecombine
- agent/description
- agent/event
- collector/ics-cert-advisory
- source/ICS
- agent/software-canonical-lookup
- agent/software-canonical-lookup-request
- agent/tags
- vendor/siemens
- canonical/siemens simatic mv420 firmware
- canonical/siemens simatic mv420
- canonical/siemens simatic mv440 firmware
- canonical/siemens simatic mv440
- vendor/multiple
- canonical/multiple nut/net, version 5.1 and prior
- canonical/multiple cyclonetcp, version 1.9.6 and prior
- canonical/multiple ndktcpip, version 2.25 and prior
- canonical/multiple fnet, version 4.6.3
- canonical/multiple uip-contiki-os (end-of-life [eol]), version 3.0 and prior
- canonical/multiple uc/tcp-ip (eol), version 3.6.0 and prior
- canonical/multiple uip-contiki-ng, version 4.5 and prior
- canonical/multiple uip (eol), version 1.0 and prior
- canonical/multiple picotcp-ng, version 1.7.0 and prior
- canonical/multiple picotcp (eol), version 1.7.0 and prior
- canonical/multiple mplab net, version 3.6.1 and prior
- canonical/multiple nucleus net, all versions prior to version 5.2
- canonical/multiple nucleus readystart for arm, mips, and ppc, all versions prior to version 2012.12