1. Ubuntu Security Notices
  2. USN-6585-1

USN-6585-1: libssh2 vulnerability

Publication date

15 January 2024

Overview

libssh2 could be made to expose sensitive information over the network.

Releases

Packages

  • libssh2 - Client-side C library implementing the SSH2 protocol

Details

Fabian Bäumer, Marcus Brinkmann, Jörg Schwenk discovered that the SSH
protocol was vulnerable to a prefix truncation attack. If a remote attacker
was able to intercept SSH communications, extension negotiation messages
could be truncated, possibly leading to certain algorithms and features
being downgraded. This issue is known as the Terrapin attack. This update
adds protocol extensions to mitigate this issue.

Fabian Bäumer, Marcus Brinkmann, Jörg Schwenk discovered that the SSH
protocol was vulnerable to a prefix truncation attack. If a remote attacker
was able to intercept SSH communications, extension negotiation messages
could be truncated, possibly leading to certain algorithms and features
being downgraded. This issue is known as the Terrapin attack. This update
adds protocol extensions to mitigate this issue.

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
23.10 mantic libssh2-1 –  1.11.0-2ubuntu0.1

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References

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