The previous chapter gave you an overall view of all the stages of the cyber-attack life cycle. This chapter will go into the first phase of the life cycle in depth—reconnaissance. Reconnaissance is one of the most important stages of a threat life cycle, where attackers search for vulnerabilities that they can use to attack targets. An attacker will be interested in locating and gathering data, and identifying any loopholes in a target's network, its users, or its computing systems. Reconnaissance is done both passively and actively, borrowing tactics that have been used by the military. It can be compared to the sending of spies into an enemy's territory to gather data about where and when to strike. When reconnaissance is done in the right way, the target should not be able to know that it is being done. This critical attack life cycle phase can be actualized in a number of ways, which are broadly classified as external and internal reconnaissance.

This chapter is going to discuss the following topics:

• External reconnaissance:
  • Dumpster diving
  • The use of social media to obtain information about the target
  • Social engineering
• Tools used to perform internal reconnaissance