Introduction to reconnaissance

Penetration testing is most effective when you have a good grasp on the environment being tested. Sometimes this information will be presented to you by the corporation that hired you, other times you will need to go out and perform your reconnaissance to learn even the most trivial of items. In either case, make sure to have the scope clarified in the rules of engagement prior to conducting any work, including reconnaissance.

Many corporations are not aware of the types of data that can be found and used by attackers in the wild. A penetration tester will need to bring this information to light. You will be providing the business with real data that they can then act upon in accordance to their risk appetite. The information that you will be able to find will vary from target to target, but will typically include items such as IP ranges, domain names, e-mail addresses, public financial data, organizational information, technologies used, job titles, phone numbers...