Information Gathering with Shodan

Shodan

Shodan, the official definition of himself Computer Search Engine (Computer Resource Search Engine), is American man John Mase Li spent nearly 10 years to build a search engine that can search almost all US industrial control and connected to the network system.

Shodan Unlike traditional search engines such as Google, use Web crawlers to traverse your entire site, but directly into the channel behind the Internet, various types of port equipment audits, and never stops looking for the Internet and all associated servers, camera, printers, routers, and so on. Shodan month will be at about 500 million servers around the clock to gather information.

Shodan only searches for network equipment. Many devices should not be connected to the Internet. However, due to the negligence and laziness of the local network administrator, the network cable is directly connected to the same network as a normal personal computer. Such as car washing machines, temperature controllers, traffic surveillance cameras, heating systems, routers, printers, cameras, servers, etc. Users can search for these devices that should not be connected to the Internet through Shodan, and obtain critical information from most unarmed devices to gain control. Hackers can use Shodan to search for numerous servers with weak firewalls to set up backdoors and turn them into botnets for cyber attacks.

Shodan works well with basic, single-term searches. Here are the basic search filters you can use:

• city: find devices in a particular city
• country: find devices in a particular country
• geo: you can pass it coordinates
• hostname: find values that match the hostname
• net: search based on an IP or /x CIDR
• os: search based on an operating system
• port: find particular ports that are open
• before/after: find results within a timeframe

Below is the list of Shodan Filters by Javier Olmedo 

General Filters

HTTP Filters

NTP Filters

SSL Filters

Telnet Filters