Amazon Linux AMI : c-ares (ALAS-2021-1545)

medium Nessus Plugin ID 154901


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


The version of c-ares installed on the remote host is prior to 1.17.2-1.8. It is, therefore, affected by a vulnerability as referenced in the ALAS-2021-1545 advisory.

- A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability. (CVE-2021-3672)

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


Run 'yum update c-ares' to update your system.

See Also

Plugin Details

Severity: Medium

ID: 154901

File Name: ala_ALAS-2021-1545.nasl

Version: 1.6

Type: local

Agent: unix

Published: 11/5/2021

Updated: 11/27/2023

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

Risk Information


Risk Factor: Medium

Score: 4.2


Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.3

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

CVSS Score Source: CVE-2021-3672


Risk Factor: Medium

Base Score: 5.6

Temporal Score: 5.1

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:c-ares, p-cpe:/a:amazon:linux:c-ares-debuginfo, p-cpe:/a:amazon:linux:c-ares-devel, cpe:/o:amazon:linux

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: 10/29/2021

Vulnerability Publication Date: 8/13/2021

Reference Information

CVE: CVE-2021-3672

ALAS: 2021-1545