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Amazon Linux 2 : openssh (ALAS-2023-2376)

medium Nessus Plugin ID 187063

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of openssh installed on the remote host is prior to 7.4p1-22. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2023-2376 advisory.

 - The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in [email protected] and (if CBC is used) the [email protected] MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD 1.3.9rc1, ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust; and there could be effects on Bitvise SSH through 9.31. (CVE-2023-48795)

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

Solution

Run 'yum update openssh' to update your system.

See Also

https://alas.aws.amazon.com/AL2/ALAS-2023-2376.html

https://alas.aws.amazon.com/cve/html/CVE-2023-48795.html

https://alas.aws.amazon.com/faqs.html

Plugin Details

Severity: Medium

ID: 187063

File Name: al2_ALAS-2023-2376.nasl

Version: 1.6

Type: local

Agent: unix

Published: 12/18/2023

Updated: 12/29/2023

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4.2

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

CVSS Score Source: CVE-2023-48795

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.3

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:openssh, p-cpe:/a:amazon:linux:openssh-askpass, p-cpe:/a:amazon:linux:openssh-cavs, p-cpe:/a:amazon:linux:openssh-clients, p-cpe:/a:amazon:linux:openssh-debuginfo, p-cpe:/a:amazon:linux:openssh-keycat, p-cpe:/a:amazon:linux:openssh-ldap, p-cpe:/a:amazon:linux:openssh-server, p-cpe:/a:amazon:linux:openssh-server-sysvinit, p-cpe:/a:amazon:linux:pam_ssh_agent_auth, cpe:/o:amazon:linux:2

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/18/2023

Vulnerability Publication Date: 12/18/2023

Reference Information

CVE: CVE-2023-48795

IAVA: 2023-A-0703