Censys
More info
- Creator
- Zakir Durumeric et al.
- Released
- 2015 (research project), company 2017
- Type
- Security company, search engine
A search engine for whatever actually answers on the internet, born out of the research that made scanning all of IPv4 an afternoon's work.
Censys started at the University of Michigan, where Zakir Durumeric and Alex Halderman had used their ZMap scanner to measure internet security as a whole. The results — open ports, service banners, TLS certificates — were made searchable for researchers in 2015, and in 2017 the project became a company in Ann Arbor.
It resembles the older Shodan but was built with an academic's appetite for coverage and structure. Defenders use it to find servers they forgot they had; attackers use it for exactly the same thing, with different intentions. When a new vulnerability like Log4Shell drops, one of the first questions is how many exposed systems are out there, and the answer often comes from here.