VulnerabilityModified
CVE-2020-12667
Knot Resolver before 5.1.1 allows traffic amplification via a crafted DNS answer from an attacker-controlled server, aka an "NXNSAttack" issue.
HIGH 7.5EPSS 2.62%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.62%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 2.62% probability · 85th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400
- Affected
- nic/knot resolver
- Source
- cve@mitre.org
References
- http://cyber-security-group.cs.tau.ac.il/#Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2020/05/19/2Mailing List, Third Party Advisory
- https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/Technical Description, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/76Y4FITMOH6RVPWAANGV7NB2ZHPJJGDQ/
- https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.htmlRelease Notes, Vendor Advisory
- http://cyber-security-group.cs.tau.ac.il/#Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2020/05/19/2Mailing List, Third Party Advisory
- https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/Technical Description, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2024/04/msg00017.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/76Y4FITMOH6RVPWAANGV7NB2ZHPJJGDQ/
- https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.htmlRelease Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.