Denial of service vulnerability in PowerDNS Recursor allows authoritative servers to be marked unavailable.This issue affects Recursor: through 4.6.5, through 4.7.4 , through 4.8.3.

In PowerDNS Authoritative Server before 4.4.3, 4.5.x before 4.5.4, and 4.6.x before 4.6.1 and PowerDNS Recursor before 4.4.8, 4.5.x before 4.5.8, and 4.6.x before 4.6.1, insufficient validation of an IXFR end condition causes incomplete zone transfers to be handled as successful transfers.

An issue has been found in PowerDNS Recursor before 4.1.18, 4.2.x before 4.2.5, and 4.3.x before 4.3.5. A remote attacker can cause the cached records for a given name to be updated to the Bogus DNSSEC validation state, instead of their actual DNSSEC Secure state, via a DNS ANY query. This results in a denial of service for installation that always validate (dnssec=validate), and for clients requesting validation when on-demand validation is enabled (dnssec=process).

In PowerDNS Recursor versions up to and including 4.3.1, 4.2.2 and 4.1.16, the ACL restricting access to the internal web server is not properly enforced.

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.

An issue has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. It allows 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 have '\0' termination of 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 always has '\0' termination.) Under some conditions, this issue can lead to the writing of one '\0' byte out-of-bounds on the stack, causing a denial of service or possibly arbitrary code execution.

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, allowing an attacker to bypass DNSSEC validation.