Threat Intelligence Database

RRSIGs with too few labels can lead to bypass of DNSSEC wildcard validation

The issue is a DNSSEC validation bypass where wildcard expansion proofs (NSEC/NSEC3 records) are accepted without signature validation when the wildcard answer is a CNAME or DNAME record.

If the auth responds very slowly and the records expire in between, the capping of TTLs is not enforced for lack of data. This does not happen on regular resolve as then then the child records are used immediately if not expired and thus valid, or the records are expired, and in that case not used. So this case can only happen if almost expired records are used to refresh the authoritative NS records.

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Spoofing replies to Recursor might mark an IP of an authoritative server as not supporting EDNS, causing valdiation of DNSSEC records served by that server to fail.

An invalid zone might pass ZONEMD validation while it should not. This is only relevant if ZoneToCache is configured with ZONEMD validation.

Incomplete validation of the SOA record present in a catalog zone might lead to a crash.

A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.

ECS zero scoped answers are stored in the packet cache while they should not. This impacts only configurations that have ECS enabled;

A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to cache poisoning.