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.

Fixes CVE-2020-10995, CVE-2020-12244 and CVE-2020-10030

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PowerDNS Team reports :

CVE-2020-10995: 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.

CVE-2020-12244: An issue has been found in PowerDNS Recursor 4.1.0 through 4.3.0 where records in the answer section of a NXDOMAIN response lacking an SOA were not properly validated in SyncRes::processAnswer. This would allow an attacker in position of man-in-the-middle to send a NXDOMAIN answer for a name that does exist, bypassing DNSSEC validation.

CVE-2020-10030: An issue has been found in PowerDNS Authoritative Server allowing an attacker with enough privileges to change the system's hostname to cause disclosure of uninitialized memory content via a stack-based out-of-bounds read. It only occurs on systems where gethostname() does not null-terminate the returned string if the hostname is larger than the supplied buffer. Linux systems are not affected because the buffer is always large enough. OpenBSD systems are not affected because the returned hostname is always null-terminated. Under some conditions this issue can lead to the writing of one null-byte out-of-bounds on the stack, causing a denial of service or possibly arbitrary code execution.

This update for pdns-recursor fixes the following issues :

  - update to 4.1.16

  - fixes an issue where records in the answer section of a     NXDOMAIN response lacking an SOA were not properly     validated (CVE-2020-12244, boo#1171553)

  - fixes an issue where invalid hostname on the server can     result in disclosure of invalid memory (CVE-2020-10030,     boo#1171553)

  - fixes an issue in the DNS protocol has been found that     allows malicious parties to use recursive DNS services     to attack third party authoritative name servers     (CVE-2020-10995, boo#1171553)

For details see https://doc.powerdns.com/recursor/changelog/4.1.html#change-4.1.16

Two vulnerabilities have been discovered in PDNS Recursor, a resolving name server; a traffic amplification attack against third-party authoritative name servers (NXNSAttack) and insufficient validation of NXDOMAIN responses lacking an SOA.

The version of pdns-recursor in the oldstable distribution (stretch) is no longer supported. If these security issues affect your setup, you should upgrade to the stable distribution (buster).

ID	Name	Product	Family	Severity
137431	Fedora 32 : pdns-recursor (2020-d9abb0c06d)	Nessus	Fedora Local Security Checks	high
137430	Fedora 31 : pdns-recursor (2020-c0ff3df740)	Nessus	Fedora Local Security Checks	high
136942	FreeBSD : powerdns-recursor -- multiple vulnerabilities (f9c5a410-9b4e-11ea-ac3f-6805ca2fa271)	Nessus	FreeBSD Local Security Checks	high
136885	openSUSE Security Update : pdns-recursor (openSUSE-2020-698)	Nessus	SuSE Local Security Checks	high
136778	Debian DSA-4691-1 : pdns-recursor - security update	Nessus	Debian Local Security Checks	high

Detections

Analytics

CVE-2020-10995

high

Tenable Plugins

high

high

high

high

high