No, WHOIS data is of such low quality that it's useless. SSL cert data is of better quality, for OV (Organization Validated) and EV (Extended validation) certs. Contact addresses found in text on the web site are also useful. Those we match to commercial business directory information.
We ignore Cloudflare's many SSL certs. We have a short blacklist of MITM-as-a-service content delivery networks. Here's my paper on that.[1]
The list is short. Here it is:
cloudflare.com – a front-end network for sites, controlling 36,280 domains.
incapsula.com – a front-end network for sites
sonymusic.com – operates sites for their range of artists.
Janrainengage.com – customer tracking service
edgecastcdn.net – Verizon caching system
fiducia.de – security service for banks
vin65.com – wine seller with many sites for various wine brands.
practiceweb.co.uk – a hosting service for accountants
Sites which use those services are not blacklisted by Sitetruth, but the ownership data in their SSL certs is ignored as meaningless. The CA/Browser Forum is looking into ways to express this better in SSL certs. A cert with fifty unrelated businesses is just silly, and it's a transitional thing until everybody gets TLS-capable OSs and browsers so shared IP doesn't mean shared cert. (Windows XP/IE 6 being the problem).
