FreeBSD : DNSSEC validators -- denial-of-service/CPU exhaustion from KeyTrap and NSEC3 vulnerabilities (21a854cc-cac1-11ee-b7a7-353f1e043d9a)

high Nessus Plugin ID 190577

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the 21a854cc-cac1-11ee-b7a7-353f1e043d9a 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)

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

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 190577

File Name: freebsd_pkg_21a854cccac111eeb7a7353f1e043d9a.nasl

Version: 1.2

Type: local

Family: FreeBSD Local Security Checks

Published: 2/15/2024

Updated: 12/25/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.1

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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

CVSS Score Source: CVE-2023-50868

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:dnsmasq-devel, p-cpe:/a:freebsd:freebsd:bind9-devel, p-cpe:/a:freebsd:freebsd:dnsmasq, p-cpe:/a:freebsd:freebsd:unbound, p-cpe:/a:freebsd:freebsd:bind918, cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:bind916, p-cpe:/a:freebsd:freebsd:powerdns-recursor

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2/13/2024

Vulnerability Publication Date: 2/13/2024

Reference Information

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

Detections

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