Open Source Intelligence
Dumpster Diving: You would be surprised at how much sensitive data is thrown out, intact, into the garbage. It may not be dignified, but bad actors can root through the trash and find private data: credit card data, personal data, medical data, company data. Be mindful when disposing of sensitive data.
Shoulder Surfing: One of the oldest tricks in the book is shoulder surfing. By looking over your shoulder or watching from beside you, a bad actor can watch you enter your username and password, or see your private data. Sure, shoulder surfing is low-tech, but this social engineering technique can be very effective.
Google Hacking: Google is a powerful tool, and with great power comes great responsibility. By performing special searches in the Google search engines, hackers can gain information about websites which they can use to exploit weaknesses. Especially vulnerable websites can even have their usernames and passwords leaked by Google Hacking.
Wayback Machine: The Wayback Machine is a website which stores snapshots of websites over a long period of time. Using the Wayback Machine, it is possible to go back and view old versions of websites and even websites that have since been removed from the internet. Time traveling on the internet, what a concept!
Open Source Intelligence: There is lots of information collected and distributed for free that can be used for intelligence (law enforcement, foreign policy, military, etc) purposes. Open-source intelligence (OSINT) can be divided up into six different categories: media, internet, public government data, academic publications, commercial data, and “grey” literature.