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

  - A vulnerability was discovered in DNS resolver component of knot resolver through version 3.2.0 before     4.1.0 which allows remote attackers to bypass DNSSEC validation for non-existence answer. NXDOMAIN answer     would get passed through to the client even if its DNSSEC validation failed, instead of sending a SERVFAIL     packet. Caching is not affected by this particular bug but see CVE-2019-10191. (CVE-2019-10190)

  - A vulnerability was discovered in DNS resolver of knot resolver before version 4.1.0 which allows remote     attackers to downgrade DNSSEC-secure domains to DNSSEC-insecure state, opening possibility of domain     hijack using attacks against insecure DNS protocol. (CVE-2019-10191)

  - 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)

  - Knot Resolver before 5.1.1 allows traffic amplification via a crafted DNS answer from an attacker-     controlled server, aka an NXNSAttack issue. This is triggered by random subdomains in the NSDNAME in NS     records. (CVE-2020-12667)

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

Detections

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Debian dla-3795 : knot-resolver - security update

high Nessus Plugin ID 193916

Version 1.0