USN-6565-1: OpenSSH vulnerabilities

Releases

• Ubuntu 23.10
• Ubuntu 23.04
• Ubuntu 22.04 LTS
• Ubuntu 20.04 LTS

Packages

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

Details

It was discovered that OpenSSH incorrectly handled supplemental groups when
running helper programs for AuthorizedKeysCommand and
AuthorizedPrincipalsCommand as a different user. An attacker could possibly
use this issue to escalate privileges. This issue only affected Ubuntu
20.04 LTS. (CVE-2021-41617)

It was discovered that OpenSSH incorrectly added destination constraints
when PKCS#11 token keys were added to ssh-agent, contrary to expectations.
This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04.
(CVE-2023-51384)

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. (CVE-2023-51385)

Update instructions

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

Ubuntu 23.10

• openssh-client - 1:9.3p1-1ubuntu3.2
• openssh-server - 1:9.3p1-1ubuntu3.2

Ubuntu 23.04

• openssh-client - 1:9.0p1-1ubuntu8.7
• openssh-server - 1:9.0p1-1ubuntu8.7

Ubuntu 22.04

• openssh-client - 1:8.9p1-3ubuntu0.6
• openssh-server - 1:8.9p1-3ubuntu0.6

Ubuntu 20.04

• openssh-client - 1:8.2p1-4ubuntu0.11
• openssh-server - 1:8.2p1-4ubuntu0.11

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

References

• CVE-2021-41617
• CVE-2023-51384
• CVE-2023-51385

Related notices

• USN-5666-1
• USN-6560-2
• USN-6560-3