1. Ubuntu Security Notices
  2. USN-6279-1

USN-6279-1: OpenSSH update

Publication date

9 August 2023

Overview

A hardening measure was added to OpenSSH.

Releases

Packages

  • openssh - secure shell (SSH) for secure access to remote machines

Details

It was discovered that OpenSSH has an observable discrepancy leading to an
information leak in the algorithm negotiation. This update mitigates the
issue by tweaking the client hostkey preference ordering algorithm to
prefer the default ordering if the user has a key that matches the
best-preference default algorithm.

It was discovered that OpenSSH has an observable discrepancy leading to an
information leak in the algorithm negotiation. This update mitigates the
issue by tweaking the client hostkey preference ordering algorithm to
prefer the default ordering if the user has a key that matches the
best-preference default algorithm.

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
20.04 focal openssh-client –  1:8.2p1-4ubuntu0.9
18.04 bionic openssh-client –  1:7.6p1-4ubuntu0.7+esm2  
16.04 xenial openssh-client –  1:7.2p2-4ubuntu2.10+esm4  
14.04 trusty openssh-client –  1:6.6p1-2ubuntu2.13+esm2  

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References

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