Vulnerability · Published May 19, 2020 · Assigned by mitre
CVE-2020-12667
High 7.5
In plain English
A high-severity uncontrolled resource consumption in the knot-resolver package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.6% (higher than 85% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)2.6%top 14.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | knot-resolver | 5.1.1-r0 | ALPINE-CVE-2020-12667 |
| Alpine:v3.21 | knot-resolver | 5.1.1-r0 | ALPINE-CVE-2020-12667 |
| Alpine:v3.22 | knot-resolver | 5.1.1-r0 | ALPINE-CVE-2020-12667 |
| Alpine:v3.23 | knot-resolver | 5.1.1-r0 | ALPINE-CVE-2020-12667 |
| Alpine:v3.24 | knot-resolver | 5.1.1-r0 | ALPINE-CVE-2020-12667 |
| Debian:12 | knot-resolver | 5.1.1-0.1 | DEBIAN-CVE-2020-12667 |
| Debian:13 | knot-resolver | 5.1.1-0.1 | DEBIAN-CVE-2020-12667 |
| Debian:14 | knot-resolver | 5.1.1-0.1 | DEBIAN-CVE-2020-12667 |
Affected products (as reported)
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://en.blog.nic.cz/2020/05/19/nxnsattack-upgrade-resolvers-to-stop-new-kind-of-random-subdomain-attack/
- https://www.knot-resolver.cz/2020-05-19-knot-resolver-5.1.1.html
- [oss-security] 20200519 [CVE-2020-12667] Knot Resolver 5.1.1 NXNSAttack mitigation mailing-list
- http://cyber-security-group.cs.tau.ac.il/#
- FEDORA-2020-bf68101ad3 vendor-advisory
- [debian-lts-announce] 20240426 [SECURITY] [DLA 3795-1] knot-resolver security update mailing-list