knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS replies with very many resource records might be processed very inefficiently, in extreme cases taking even several CPU seconds for each such uncached message. For example, a few thousand A records can be squashed into one DNS message (limit is 64kB).

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS     replies with very many resource records might be processed very inefficiently, in extreme cases taking     even several CPU seconds for each such uncached message. For example, a few thousand A records can be     squashed into one DNS message (limit is 64kB). (CVE-2019-19331)

Note that Nessus relies on the presence of the package as reported by the vendor.

The remote Ubuntu 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-7047-1 advisory.

    Vladimr unt discovered that Knot Resolver incorrectly handled input during DNSSEC validation. A     remote attacker could possibly use this issue to bypass certain validations. (CVE-2019-10190)

    Vladimr unt discovered that Knot Resolver incorrectly handled input during DNSSEC validation. A     remote attacker could possibly use this issue to downgrade DNSSEC-secure domains to a DNSSEC-insecure     state, resulting

    in a domain hijacking attack. (CVE-2019-10191)

    Vladimr unt discovered that Knot Resolver incorrectly handled certain

    DNS replies with many resource records. An attacker could possibly use

    this issue to consume system resources, resulting in a denial of service. (CVE-2019-19331)

    Lior Shafir, Yehuda Afek, and Anat Bremler-Barr discovered that Knot Resolver incorrectly handled certain     queries. A remote attacker could

    use this issue to perform an amplification attack directed at a target. (CVE-2020-12667)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

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

The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3795 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-3795-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                      Markus Koschany     April 26, 2024                                https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : knot-resolver     Version        : 3.2.1-3+deb10u2     CVE ID         : CVE-2019-10190 CVE-2019-10191 CVE-2019-19331 CVE-2020-12667     Debian Bug     : 932048 946181 961076

    Several security vulnerabilities have been discovered in knot-resolver, a     caching, DNSSEC-validating DNS resolver which may allow remote attackers to     bypass DNSSEC validation or cause a denial-of-service.

    For Debian 10 buster, these problems have been fixed in version     3.2.1-3+deb10u2.

    We recommend that you upgrade your knot-resolver packages.

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

    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.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - knot-resolver before version 4.3.0 is vulnerable to denial of service through high CPU utilization. DNS
    replies with very many resource records might be processed very inefficiently, in extreme cases taking
    even several CPU seconds for each such uncached message. For example, a few thousand A records can be
    squashed into one DNS message (limit is 64kB). (CVE-2019-19331)

- update to upstream version 4.3.0

  - fixes CVE-2019-19331

  - root.keys is moved to /var/lib/knot-resolver -     knot-resolver no longer requires write permission to     /etc/knot-resolver/

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
256427	Linux Distros Unpatched Vulnerability : CVE-2019-19331	Nessus	Misc.	high
207977	Ubuntu 20.04 LTS : Knot Resolver vulnerabilities (USN-7047-1)	Nessus	Ubuntu Local Security Checks	high
193916	Debian dla-3795 : knot-resolver - security update	Nessus	Debian Local Security Checks	high
405081	Alpine: multiple knot-resolver packages: security update to 4.3.0-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
405081	Alpine: multiple knot-resolver packages: security update to 4.3.0-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
132029	Fedora 31 : knot-resolver (2019-866dc03603)	Nessus	Fedora Local Security Checks	high
132028	Fedora 30 : knot-resolver (2019-44ccfa9b29)	Nessus	Fedora Local Security Checks	high

Detections

Analytics

CVE-2019-19331

high

Tenable Plugins

high

high

high

high

high

high

high