Description
PowerDNS Recursor from 4.1.0 up to and including 4.3.0 does not sufficiently defend against amplification attacks. An issue in the DNS protocol has been found that allow malicious parties to use recursive DNS services to attack third party authoritative name servers. The attack uses a crafted reply by an authoritative name server to amplify the resulting traffic between the recursive and other authoritative name servers. Both types of service can suffer degraded performance as an effect. This is triggered by random subdomains in the NSDNAME in NS records. PowerDNS Recursor 4.1.16, 4.2.2 and 4.3.1 contain a mitigation to limit the impact of this DNS protocol issue.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pdns-recursor | 4.3.1-1 | — |
| Debian 13 | pdns-recursor | 4.3.1-1 | — |
| Debian 12 | pdns-recursor | 4.3.1-1 | — |
| Debian 10 | pdns-recursor | 4.1.11-1+deb10u1 | DSA-4691-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 18.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 16.04 LTS | pdns-recursor | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
| SUSE Package Hub 12 SP1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | pdns-recursor | 4.5.5-1.3 | openSUSE-SU-2024:11157-1 |
| openSUSE Leap 15.1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.23 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.22 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.21 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.20 | pdns-recursor | 4.3.1-r0 | — |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.18 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.17 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.16 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.15 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.14 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.13 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.12 | pdns-recursor | 4.3.1-r0 | — |
| Alpine v3.11 | pdns-recursor | 4.2.2-r0 | — |
| Alpine v3.10 | pdns-recursor | 4.1.16-r0 | — |
| Alpine v3.9 | pdns-recursor | 4.1.16-r0 | — |
Advisories 4
- DSA-4691-1 pdns-recursor - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11157-1 pdns-recursor-4.5.5-1.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0698-1 Security update for pdns-recursor SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-0978 Mehrere DNS Server: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Oct 1, 2024
References
- http://www.nxnsattack.com
- https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2020-01.html
- DSA-4691 vendor-advisory
- openSUSE-SU-2020:0698 vendor-advisory
- FEDORA-2020-d9abb0c06d vendor-advisory
- FEDORA-2020-c0ff3df740 vendor-advisory