Downloads the Botvrij.eu public IOC domain list (no API key required),
caches it in-process with a 6h TTL, and flags any registered domain
that appears directly or as a parent of a feed entry.
ThreatFox queries the IOC database for domain indicators (C2 servers,
malware distribution, phishing); MalwareBazaar searches for malware
samples tagged with the domain. Both require a free abuse.ch Auth-Key.
