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Ubuntu 23.10: USN-6561-1 Critical: Libssh Prefix Truncation Attack

ubuntu
Calendar Grey December 19, 2023
Dist Ubuntu Esm H88
A fix has been deployed to mitigate the newly discovered libssh security flaw impacting various editions of Ubuntu.
A security issue was fixed in libssh.

Summary

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 23.10 - Ubuntu 23.04 - Ubuntu 22.04 LTS - Ubuntu 20.04 LTS Summary: A security issue was fixed in libssh. Software Description: - libssh: A tiny C SSH library 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.

Topics%20covered

Topics Covered

security advisory critical remote attack Ubuntu libssh prefix truncation

Update Instructions

The problem can be corrected by updating your system to the following package versions: Ubuntu 23.10: libssh-4 0.10.5-3ubuntu1.1 Ubuntu 23.04: libssh-4 0.10.4-2ubuntu0.2 Ubuntu 22.04 LTS: libssh-4 0.9.6-2ubuntu0.22.04.2 Ubuntu 20.04 LTS: libssh-4 0.9.3-2ubuntu2.4 In general, a standard system update will make all the necessary changes.

References

https://ubuntu.com/security/notices/USN-6561-1

CVE-2023-48795

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-6561-1

Topics%20covered

Topics Covered

security advisory critical remote attack Ubuntu libssh prefix truncation

Package Information

https://launchpad.net/ubuntu/+source/libssh/0.10.5-3ubuntu1.1 https://launchpad.net/ubuntu/+source/libssh/0.10.4-2ubuntu0.2 https://launchpad.net/ubuntu/+source/libssh/0.9.6-2ubuntu0.22.04.2 https://launchpad.net/ubuntu/+source/libssh/0.9.3-2ubuntu2.4

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