recursor

An issue has been found in PowerDNS Recursor versions after 4.1.3 before 4.1.9 where Lua hooks are not properly applied to queries received over TCP in some specific combination of settings, possibly bypassing security policies enforced using Lua.

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 before version 4.1.8 where a remote attacker sending a DNS query can trigger an out-of-bounds memory read while computing the hash of the query for a packet cache lookup, possibly leading to a crash.

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.

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

An issue has been found in the parsing of authoritative answers in PowerDNS Recursor before 4.0.8, leading to a NULL pointer dereference when parsing a specially crafted answer containing a CNAME of a different class than IN. An unauthenticated remote attacker could cause a denial of service.

A remote attacker might be able to cause infinite recursion in PowerDNS Recursor 4.8.0 via a DNS query that retrieves DS records for a misconfigured domain, because QName minimization is used in QM fallback mode. This is fixed in 4.8.1.

An attacker can trigger the removal of cached records by sending a NOTIFY query over TCP.

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.

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).

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.

PowerDNS Recursor up to and including 4.5.9, 4.6.2 and 4.7.1, when protobuf logging is enabled, has Improper Cleanup upon a Thrown Exception, leading to a denial of service (daemon crash) via a DNS query that leads to an answer with specific properties.

A cross-site scripting issue has been found in the web interface of PowerDNS Recursor from 4.0.0 up to and including 4.0.6, where the qname of DNS queries was displayed without any escaping, allowing a remote attacker to inject HTML and Javascript code into the web interface, altering the content.

An issue has been found in the DNSSEC validation component of PowerDNS Recursor from 4.0.0 and up to and including 4.0.6, where the signatures might have been accepted as valid even if the signed data was not in bailiwick of the DNSKEY used to sign it. This allows an attacker in position of man-in-the-middle to alter the content of records by issuing a valid signature for the crafted records.

An issue has been found in the DNSSEC parsing code of PowerDNS Recursor from 4.0.0 up to and including 4.0.6 leading to a memory leak when parsing specially crafted DNSSEC ECDSA keys. These keys are only parsed when validation is enabled by setting dnssec to a value other than off or process-no-validate (default).

An issue has been found in PowerDNS before 3.4.11 and 4.0.2, and PowerDNS recursor before 3.7.4 and 4.0.4, allowing a remote, unauthenticated attacker to cause an abnormal CPU usage load on the PowerDNS server by sending crafted DNS queries, which might result in a partial denial of service if the system becomes overloaded. This issue is based on the fact that the PowerDNS server parses all records present in a query regardless of whether they are needed or even legitimate. A specially crafted query containing a large number of records can be used to take advantage of that behaviour.

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.

An issue has been found in PowerDNS Recursor from 4.0.0 up to and including 4.1.4. A remote attacker sending a DNS query for a meta-type like OPT can lead to a zone being wrongly cached as failing DNSSEC validation. It only arises if the parent zone is signed, and all the authoritative servers for that parent zone answer with FORMERR to a query for at least one of the meta-types. As a result, subsequent queries from clients requesting DNSSEC validation will be answered with a ServFail.

An issue has been found in PowerDNS before 3.4.11 and 4.0.2, and PowerDNS recursor before 4.0.4, allowing an attacker in position of man-in-the-middle to alter the content of an AXFR because of insufficient validation of TSIG signatures. A missing check that the TSIG record is the last one, leading to the possibility of parsing records that are not covered by the TSIG signature.