Beginning a career in ethical hacking and/or penetration testing can be very exciting and, most of the time, our minds will be a bit overwhelmed, causing us to visit only the chapters about exploiting a system in a book such as this. However, conducting a penetration test is like starting a new project at home. Before you build a pool in your backyard, there are a few things you must consider, such as the space that's available, the cost of materials, the contractor's fees, and other details. Information gathering is a very important phase of the hacking life cycle and penetration testing.

In this chapter, we will focus on passive information gathering techniques and methods. We will learn how to use the internet to get us the information and specific details we need about our target by using both online resources and tools on Kali Linux.

We will be covering the following topics:

• Reconnaissance and footprinting
• Understanding passive information gathering
• Understanding open source intelligence (OSINT)
• Using the top OSINT tools
• Identifying target technologies and security controls
• Finding data leaks in cloud resources
• Understanding whois and copying websites with HTTrack
• Finding subdomains using Sublist3r