Take a list of domains and inspect their NameServer domains which return an NXDOMAIN response to dig. This could indicate a NameServer domain takeover issue, which could be pretty impactful!
$ cat domains | nsfckup -c 50 -v
or
$ assetfinder example.com | nsfckup -c 50
or
$ nsfckup example.com
-c int
set the concurrency level (default 20)
-s Be strict on CNAME, must include the target domain
-v Get more info on attempts
go install github.com/cybercdh/nsfckup@latest
A lot of Go concepts were taken from @tomnomnom's excellent repos, particularly httprobe