Shodan: Scanning the Entire Internet
Google searches web content; Shodan searches service banners and metadata from devices connected to the internet. Shodan is an active reconnaissance tool operated by a third party, meaning it's used passively by the hacker.
How Shodan Works
Shodan continuously scans the entire IPv4 space on common ports (80, 21, 22, 23, 443, etc.) and records the response banners, which often reveal the operating system, specific software version, and configuration details.
Security Relevance
Hackers use Shodan to find:
- Vulnerable Services: Searching for
product: 'Apache' version: 2.2.8quickly identifies targets running obsolete, vulnerable software. - Exposed Devices: Finding open webcams, industrial control systems (ICS), or databases exposed directly to the internet.
- Specific Organization Assets: Using filters like
org: 'Target Corp'or IP ranges.
Example Search: port: 3389 country: US (Finds all RDP servers exposed in the US).