When John Matherly released SHODAN, search engine which could collect data on web servers like HTTP port 80, FTP etc. It was considered a success, in the hackers point of view. And now there’s censys.
Censys is just like shodan but, more user friendly and works in a better and broader way. Censys is like a time saving buddy for the system lovers or the so called hackers.
HOW CENSYS WORKS
Millions of devices like the home routers, ip cameras, mobile phones use same set of cryptographic keys for SSH secure shells or https. Which makes them vulnerable to hijacking. The vendors build and deploy their products. Typically, the vendors build their device’s firmware based on software development kits (SDKs) received from chip makers. They are too lazy to change the codes.
Censys conducts a daily scan on whole internet database almost everything. It scans all the IPv4 addresses which controls the majority internet traffic. It makes sure that it checks all the possible vulnerabilities. When researcher conducted the mass scan of 4 billion ip addresses the result was shocking.
“We have found everything from ATMs and bank safes to industrial control systems for power plants. It’s kind of scary,” said Zakir Durumeric, the researcher leading the Censys project at the University of Michigan and inventor of ZMap. Censys uses mainly two tools.
The first step of collecting data is Zmap(20) it performs single packet host discovery and scans all the Ipv4 address space. Hosts found by ZMap seed pluggable application scanners, which perform a followup application layer handshake and produce structured JSON data describing a certain aspect of how a host is configured. Typically, application scanners only perform a single handshake and measure one aspect of how a service is configured. For example, they perform separate horizontal scans and use different pluggable scanners to measure how HTTPS hosts respond to a typical TLS handshake, whether hosts support SSLv3, and whether a host is vulnerable to the heart bleed attack. Since collecting all the data from a single scan may cause load on the host., it instead uses scheduled scans thereby aggregating the data collected from each scheduled scans.
It is a fast and more extensible application scanner. At this time, ZGrab supports application handshakes for HTTP, HTTP Proxy, HTTPS, SMTP(S), IMAP(S), POP3(S), FTP, CWMP, SSH, and Modbus, as well as StartTLS, Heartbleed, SSLv3, and specific cipher suite checks. On a dual-Xeon E5-2640 (6-cores at 2.5 GHz) system with an Intel X520 ethernet adapter, ZGrab can complete HTTPS handshakes with the full IPv4 address space in 6h20m, and a banner grab and StartTLS connection with all publicly accessible SMTP hosts in 3h9m, 1.86k and 1.32k hosts/second respectively. In simple words ZMap quickly identifies hosts and ZGrab produces structured data about each of those hosts. Zgrab can be used independently. It does on even on one host from simply reading and writing a data to initiating a handshake.
Censys exposes data back to the community, which ranges from researchers who need to quickly perform a simple query to those who want to perform in-depth analysis on raw data. In order to meet these disparate needs, they are exposing the data to researchers through several interfaces, which offer varying degrees of flexibility.
- a web-based query and reporting interface,
- a programmatic REST API,
- Public Google BigQuery
- Raw downloadable scan results. They are planning to publish pre-defined dashboards that are accessible to users outside of the research community.