Convert IPs to CIDR ranges to expand network attack surface

go get -u github.com/daehee/cidra

Download the latest ip2asn.com database to working directory:

wget https://iptoasn.com/data/ip2asn-combined.tsv.gz

Pipe in list of IP addresses resolved from target subdomains:

cat giant-list-of-ips.txt | cidra

Add resulting CIDRs to your next nmap or masscan run.