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Amazon Linux 2023 : openssh, openssh-clients, openssh-keycat (ALAS2023-2024-651)

high Nessus Plugin ID 202916

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2024-651 advisory.

 A signal handler race condition vulnerability was found in OpenSSH's server (sshd), where a client does not authenticate within LoginGraceTime seconds (120 by default, 600 in old OpenSSH versions), then sshd's SIGALRM handler is called asynchronously. However, this signal handler calls various functions that are not async-signal-safe, for example, syslog(). This issue leaves it vulnerable to a signal handler race condition on the cleanup_exit() function, which introduces the same vulnerability as CVE-2024-6387 in the unprivileged child of the SSHD server. (CVE-2024-6409)

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

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

Solution

Run 'dnf update openssh --releasever 2023.5.20240722' to update your system.

See Also

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

https://alas.aws.amazon.com/cve/html/CVE-2024-6409.html

https://alas.aws.amazon.com/AL2023/ALAS-2024-651.html

Plugin Details

Severity: High

ID: 202916

File Name: al2023_ALAS2023-2024-651.nasl

Version: 1.1

Type: local

Agent: unix

Published: 7/22/2024

Updated: 7/22/2024

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

Risk Information

VPR

Risk Factor: High

Score: 8.0

CVSS v2

Risk Factor: Medium

Base Score: 6.6

Temporal Score: 4.9

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

CVSS Score Source: CVE-2024-6409

CVSS v3

Risk Factor: High

Base Score: 7

Temporal Score: 6.1

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:openssh, 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-server, p-cpe:/a:amazon:linux:pam_ssh_agent_auth, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:openssh-clients-debuginfo, p-cpe:/a:amazon:linux:openssh-debugsource, p-cpe:/a:amazon:linux:openssh-keycat-debuginfo, p-cpe:/a:amazon:linux:openssh-server-debuginfo, p-cpe:/a:amazon:linux:pam_ssh_agent_auth-debuginfo

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/18/2024

Vulnerability Publication Date: 7/3/2024

Reference Information

CVE: CVE-2024-6409

IAVA: 2024-A-0375