Amazon Linux 2 : systemd, --advisory ALAS2-2021-1647 (ALAS-2021-1647)

high Nessus Plugin ID 150993

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Synopsis

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

Description

The version of systemd installed on the remote host is prior to 219-78. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2021-1647 advisory.

It was discovered that systemd is vulnerable to a state injection attack when deserializing the state of a service. Properties longer than LINE_MAX are not correctly parsed and an attacker may abuse this flaw in particularly configured services to inject, change, or corrupt the service state. (CVE-2018-15686)

A memory leak was discovered in the systemd-login when a power-switch event is received. A physical attacker may trigger one of these events and leak bytes due to a missing free. (CVE-2019-20386)

A memory leak was discovered in the backport of fixes for CVE-2018-16864 in Red Hat Enterprise Linux.
Function dispatch_message_real() in journald-server.c does not free the memory allocated by set_iovec_field_free() to store the `_CMDLINE=` entry. A local attacker may use this flaw to make systemd- journald crash. (CVE-2019-3815)

Tenable has extracted the preceding description block directly from the tested product 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

Run 'yum update systemd' or or 'yum update --advisory ALAS2-2021-1647' to update your system.

Plugin Details

Severity: High

ID: 150993

File Name: al2_ALAS-2021-1647.nasl

Version: 1.9

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 6/24/2021

Updated: 9/26/2025

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.6

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

CVSS Score Source: CVE-2018-15686

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/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:amazon:linux:2, p-cpe:/a:amazon:linux:systemd-debuginfo, p-cpe:/a:amazon:linux:systemd, p-cpe:/a:amazon:linux:systemd-sysv, p-cpe:/a:amazon:linux:systemd-devel, p-cpe:/a:amazon:linux:systemd-python, p-cpe:/a:amazon:linux:systemd-libs, p-cpe:/a:amazon:linux:libgudev1, p-cpe:/a:amazon:linux:libgudev1-devel, p-cpe:/a:amazon:linux:systemd-networkd, p-cpe:/a:amazon:linux:systemd-resolved, p-cpe:/a:amazon:linux:systemd-journal-gateway

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: 6/16/2021

Vulnerability Publication Date: 10/26/2018

Reference Information

CVE: CVE-2018-15686, CVE-2019-20386, CVE-2019-3815

ALAS: 2021-1647

Detections

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