Amazon Linux 2 : unbound (ALAS-2024-2481)

high Nessus Plugin ID 191515

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Synopsis

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

Description

The version of unbound installed on the remote host is prior to 1.7.3-15. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2024-2481 advisory.

Certain DNSSEC aspects of the DNS protocol (in RFC 4035 and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses when there is a zone with many DNSKEY and RRSIG records, aka the KeyTrap issue. The protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records. (CVE-2023-50387)

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the NSEC3 issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations. (CVE-2023-50868)

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 unbound' to update your system.

Plugin Details

Severity: High

ID: 191515

File Name: al2_ALAS-2024-2481.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 3/5/2024

Updated: 12/11/2024

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

Risk Information

VPR

Risk Factor: Medium

Score: 5.1

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2023-50387

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:unbound-devel, p-cpe:/a:amazon:linux:python2-unbound, p-cpe:/a:amazon:linux:unbound-debuginfo, p-cpe:/a:amazon:linux:unbound-libs, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:unbound, p-cpe:/a:amazon:linux:python3-unbound

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

Exploit Ease: No known exploits are available

Patch Publication Date: 2/29/2024

Vulnerability Publication Date: 2/13/2024

Reference Information

CVE: CVE-2023-50387, CVE-2023-50868

Detections

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