Shodan: Getting Started Guide

Let’s dive into the fascinating world of Shodan, a powerful search engine that scans the web for devices connected to the internet. Whether you’re a penetration tester, a cybersecurity enthusiast, or just curious about exploring the digital landscape, Shodan can be an invaluable tool. Here’s a step-by-step guide to get you started:

What Is Shodan?

Shodan is like Google, but instead of indexing website content, it scans the entire internet for devices with open ports. It identifies connected devices such as routers, webcams, servers, and industrial control systems. Here are some key features of Shodan:

1. Search Filters: Shodan offers various search filters to pinpoint specific devices, services, or vulnerabilities. You can filter by device type, operating system, country, port, and more.
2. Banner Information: Shodan collects “banner” information from devices, including software versions, operating systems, open ports, and metadata. This data helps identify potential vulnerabilities.
3. Exploit Finder: Shodan identifies systems running software versions known to have vulnerabilities, aiding in preventing security breaches.
4. Network Mapping: You can identify all internet-facing assets associated with a specific IP or company, understanding the full extent of an organization’s attack surface.
5. IoT Device Discovery: Shodan excels at discovering Internet of Things (IoT) devices, which are often not securely configured by default.

How Does Shodan Work?

1. Shodan scans IP addresses for connected devices.
2. When it finds open ports, it captures information about the services running on them (a process called “banner grabbing”).
3. Shodan organizes this data into a searchable database.

Using Shodan Effectively: A Quick Overview

1. Search Queries: Start by using search queries to find specific devices or services. For example:
   • port:80: Find devices with port 80 open (HTTP).
   • country:US port:3389: Locate devices in the US with port 3389 open (RDP).
2. Shodan Dorks: Dorks are specialized search queries that help you discover specific vulnerabilities or misconfigured devices. Here are a few examples:
   • ssl.version:sslv2: Search for devices using SSLv2 (potentially insecure) ¹.
   • webcam: Find webcams accessible on the internet.
   • product:"Apache httpd": Locate Apache web servers.
3. Legal Considerations: Always use Shodan responsibly and within legal boundaries. Respect privacy and avoid unauthorized access.

Example Use Cases

1. Identifying Vulnerable Services: Search for devices running outdated software versions or known vulnerabilities.
2. Mapping an Organization’s Assets: Understand an organization’s internet-facing devices.
3. IoT Security Research: Explore IoT devices and their configurations.

Resources

• How to Use Shodan for Pentesting: A Step-By-Step Guide: A comprehensive guide with examples.
• Shodan Pentesting Guide: Covers interfaces, search query syntax, and dorks.
• Shodan Dork Cheat Sheet: Essential search queries for cybersecurity professionals.

Remember, with great power comes great responsibility. Happy exploring!

-jT @majorjoker