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Ubuntu Security Notice USN-7047-1
October 01, 2024

knot-resolver vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in knot-resolver.

Software Description:
- knot-resolver: caching, DNSSEC-validating DNS resolver

Details:

Vladimír Čunát 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)

Vladimír Čunát 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)

Vladimír Čunát 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)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
  knot-resolver                   3.2.1-3ubuntu2.2

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-7047-1
  CVE-2019-10190, CVE-2019-10191, CVE-2019-19331, CVE-2020-12667

Package Information:
  https://launchpad.net/ubuntu/+source/knot-resolver/3.2.1-3ubuntu2.2