Ubuntu 20.04 LTS / 22.04 LTS / 23.04 / 23.10 : OpenSSH vulnerabilities (USN-6560-1)

critical Nessus Plugin ID 187105

Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 20.04 LTS / 22.04 LTS / 23.04 / 23.10 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-6560-1 advisory.

Fabian Bumer, Marcus Brinkmann, Jrg 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)

Luci Stanescu discovered that OpenSSH incorrectly added destination constraints when smartcard keys were added to ssh-agent, contrary to expectations. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04.
(CVE-2023-28531)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-6560-1

Plugin Details

Severity: Critical

ID: 187105

File Name: ubuntu_USN-6560-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 12/19/2023

Updated: 8/28/2024

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2023-28531

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:23.10, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:openssh-client, p-cpe:/a:canonical:ubuntu_linux:ssh, cpe:/o:canonical:ubuntu_linux:23.04, p-cpe:/a:canonical:ubuntu_linux:openssh-tests, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:openssh-server, p-cpe:/a:canonical:ubuntu_linux:ssh-askpass-gnome, p-cpe:/a:canonical:ubuntu_linux:openssh-sftp-server

Required KB Items: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/19/2023

Vulnerability Publication Date: 3/17/2023

Reference Information

CVE: CVE-2023-28531, CVE-2023-48795

IAVA: 2023-A-0152-S, 2023-A-0703

USN: 6560-1