Assuming that initial target acquisition and nonintrusive probing haven't turned up any immediate avenues of conquest, and attacker will next turn to identifying valid user accounts or poorly protected resource shares. There are many ways to extract valid account or extracted resoure names from systems, a process we call enumeration.

      The key difference between previously discussed infromation-gathering techniques (Footprinting & Scanning) and enumeration is in the level of intrusiveness. Enumeration involves active connections to systems and directed queries. Adsuch, they may (should!) be loggedd or otherwise noticed.

      Much of the information garnered through enumeration may appear harmless at first glance. However, the information that leaks from the following holes can be your undoing. In general, once a valid username or share is enumerated, it's usually only a matter of time before the intruder guesses the corresponding password or identifies some weakness associated with the resource sharing protocol. By closing these easily fixed loopholes, you eliminate the first foothold of the hacker.

      Enumerarion techniques are mostly Operating-System specific and thus targeted using information gathered through portscans and OS detection. By knowing what types of information hackers are after and how your specific system divulges it, you can take steps to seal these labels.