CVE-2020-10995

NameCVE-2020-10995
DescriptionPowerDNS 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDSA-4691-1
NVD severitymedium

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
pdns-recursor (PTS)jessie3.6.2-2+deb8u4vulnerable
jessie (security)3.6.2-2+deb8u3vulnerable
stretch4.0.4-1+deb9u4vulnerable
stretch (security)4.0.4-1+deb9u3vulnerable
buster4.1.11-1vulnerable
buster (security)4.1.11-1+deb10u1fixed
bullseye, sid4.3.1-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pdns-recursorsource(unstable)4.3.1-1
pdns-recursorsourcebuster4.1.11-1+deb10u1DSA-4691-1
pdns-recursorsourcestretch(unfixed)end-of-life

Notes

[stretch] - pdns-recursor <end-of-life> (No longer supported, see DSA 4691)
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2020-01.html
https://www.openwall.com/lists/oss-security/2020/05/19/3

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