CVE-2019-6475 — Insufficient Verification of Data Authenticity in Bind

Mirror zones are a BIND feature allowing recursive servers to pre-cache zone data provided by other servers. A mirror zone is similar to a zone of type secondary, except that its data is subject to DNSSEC validation before being used in answers, as if it had been looked up via traditional recursion, and when mirror zone data cannot be validated, BIND falls back to using traditional recursion instead of the mirror zone. However, an error in the validity checks for the incoming zone data can allow…