CVE-2020-27213
First published: Tue Oct 10 2023(Updated: )
An issue was discovered in Ethernut Nut/OS 5.1. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. While the ISN generator seems to adhere to RFC 793 (where a global 32-bit counter is incremented roughly every 4 microseconds), proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Ethernut nut/os | =5.1 | |
| open-iscsi | ||
| CycloneTCP | ||
| Multiple NDKTCPIP, Version 2.25 and prior | ||
| butok FNET | ||
| Contiki OS | ||
| uC/TCP-IP | ||
| Contiki-NG | ||
| uIP (EOL) | ||
| altran picoTCP-NG | ||
| picoTCP | ||
| MPLAB Net | ||
| Multiple Nucleus NET | ||
| Multiple Nucleus ReadyStart for ARM, MIPS, and PPC |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2020-27213?
CVE-2020-27213 is considered a critical vulnerability due to its potential to allow TCP connection hijacking.
What products are affected by CVE-2020-27213?
CVE-2020-27213 impacts multiple products including Ethernut Nut/OS 5.1, CycloneTCP 1.9.6 and prior, and various other TCP/IP stacks.
How do I fix CVE-2020-27213?
To mitigate CVE-2020-27213, it is recommended to update to the latest secure version of the affected software.
What is the cause of CVE-2020-27213?
CVE-2020-27213 is caused by the use of an insufficiently random source for generating Initial Sequence Numbers in TCP connections.
Can CVE-2020-27213 allow unauthorized access?
Yes, CVE-2020-27213 may allow an attacker to hijack existing TCP connections, leading to unauthorized access.
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- vendor/ethernut
- canonical/ethernut nut/os
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