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USN-6560-2: OpenSSH vulnerabilities

11 January 2024

Several security issues were fixed in OpenSSH.

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Releases

Packages

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

Details

USN-6560-1 fixed several vulnerabilities in OpenSSH. This update provides
the corresponding update for Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.

Original advisory 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. (CVE-2023-48795)

It was discovered that OpenSSH incorrectly handled user names or host names
with shell metacharacters. An attacker could possibly use this issue to
perform OS command injection. This only affected Ubuntu 18.04 LTS. (CVE-2023-51385)

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04

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

Related notices

  • USN-6560-1: ssh-askpass-gnome, openssh-sftp-server, ssh, openssh-server, openssh-tests, openssh-client, openssh
  • USN-6561-1: libssh-gcrypt-4, libssh-dev, libssh-4, libssh-doc, libssh, libssh-gcrypt-dev
  • USN-6585-1: libssh2-1, libssh2-1-dev, libssh2
  • USN-6589-1: filezilla, filezilla-common
  • USN-6598-1: paramiko-doc, paramiko, python3-paramiko
  • USN-6565-1: ssh-askpass-gnome, openssh-sftp-server, ssh, openssh-server, openssh-tests, openssh-client, openssh