Debian dla-3371 : libunbound-dev - security update

medium Nessus Plugin ID 214466

Synopsis

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

Description

The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3371 advisory.

------------------------------------------------------------------------- Debian LTS Advisory DLA-3371-1 [email protected] https://www.debian.org/lts/security/ Markus Koschany March 29, 2023 https://wiki.debian.org/LTS
-------------------------------------------------------------------------

Package : unbound Version : 1.9.0-2+deb10u3 CVE ID : CVE-2020-28935 CVE-2022-3204 CVE-2022-30698 CVE-2022-30699 Debian Bug : 1016493 977165

Several security vulnerabilities have been discovered in unbound, a validating, recursive, caching DNS resolver.

CVE-2022-3204

A vulnerability named 'Non-Responsive Delegation Attack' (NRDelegation Attack) has been discovered in various DNS resolving software. The NRDelegation Attack works by having a malicious delegation with a considerable number of non responsive nameservers. The attack starts by querying a resolver for a record that relies on those unresponsive nameservers. The attack can cause a resolver to spend a lot of time/resources resolving records under a malicious delegation point where a considerable number of unresponsive NS records reside. It can trigger high CPU usage in some resolver implementations that continually look in the cache for resolved NS records in that delegation. This can lead to degraded performance and eventually denial of service in orchestrated attacks.
Unbound does not suffer from high CPU usage, but resources are still needed for resolving the malicious delegation. Unbound will keep trying to resolve the record until hard limits are reached. Based on the nature of the attack and the replies, different limits could be reached. From now on Unbound introduces fixes for better performance when under load, by cutting opportunistic queries for nameserver discovery and DNSKEY prefetching and limiting the number of times a delegation point can issue a cache lookup for missing records.

CVE-2022-30698 and CVE-2022-30699

Unbound is vulnerable to a novel type of the ghost domain names attack.
The vulnerability works by targeting an Unbound instance.
Unbound is queried for a rogue domain name when the cached delegation information is about to expire. The rogue nameserver delays the response so that the cached delegation information is expired. Upon receiving the delayed answer containing the delegation information, Unbound overwrites the now expired entries. This action can be repeated when the delegation information is about to expire making the rogue delegation information ever-updating. From now on Unbound stores the start time for a query and uses that to decide if the cached delegation information can be overwritten.

CVE-2020-28935

Unbound contains a local vulnerability that would allow for a local symlink attack.

For Debian 10 buster, these problems have been fixed in version 1.9.0-2+deb10u3.

We recommend that you upgrade your unbound packages.

For the detailed security status of unbound please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/unbound

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS Attachment:
signature.asc Description: This is a digitally signed message part

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the libunbound-dev packages.

Plugin Details

Severity: Medium

ID: 214466

File Name: debian_DLA-3371.nasl

Version: 1.1

Type: local

Agent: unix

Family: Debian Local Security Checks

Published: 1/22/2025

Updated: 1/22/2025

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

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.6

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

CVSS Score Source: CVE-2020-28935

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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

CVSS Score Source: CVE-2022-30699

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:10.0, p-cpe:/a:debian:debian_linux:libunbound-dev, p-cpe:/a:debian:debian_linux:python-unbound, p-cpe:/a:debian:debian_linux:unbound, p-cpe:/a:debian:debian_linux:unbound-anchor, p-cpe:/a:debian:debian_linux:unbound-host, p-cpe:/a:debian:debian_linux:libunbound8, p-cpe:/a:debian:debian_linux:python3-unbound

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 3/29/2023

Vulnerability Publication Date: 12/7/2020

Reference Information

CVE: CVE-2020-28935, CVE-2022-30698, CVE-2022-30699, CVE-2022-3204

Detections

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