CVE-2020-10995

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.