footprint of an organization from which they can launch an attack. By following some simple advice, network administrators can make footprinting more difficult. Figure outlines the process detailed below. Hackers can build a complete profile or “footprint” of the company security posture. Using a range of tools and techniques, an attacker can discover the company domain names; network blocks; IP addresses of systems, ports, and services used; and many other details pertaining to the company security posture as related to the Internet, an intranet, remote access, and an extranet. In a simple scenario, an attacker might start with the company web page. A web page can lead to other sources of information. After the hacker has the company domain name (an easy thing to find), determining the IP addresses of servers and devices is relatively easy. In another scenario, assume that the footprint reveals a recently acquired startup company. Assume as well that this startup company has weaker security than the new parent company. The attacker may be able to use this weakness, possibly through poorly protected virtual private network (VPN) links. Building a footprint, or “footprinting,” is an iterative process. Initially, footprinting provides a number of hostnames, their IP addresses, and a basic picture of the network topology. Hackers can use the whois databases maintained by the InterNIC and domain name registrars to build on this information. WHOIS databases contain name server, registrar, and, in some cases, full contact information about a domain name. The InterNIC maintains a central registry whois database containing only registrar and name server information for all .com, .net, and .org domains. However, each registrar must maintain a whois database containing all of the contact information for the domains that they host. These are some of the tools used in footprinting: Figure outlines some basic steps to take to make footprinting more difficult:
Content 5.1 Thinking Like a Hacker 5.1.3 Step 2: Enumerate Information Footprinting generates a map of the target network. Enumeration is the effort aimed at building on the footprint and compiling more specific network data. Hackers are interested in finding this information : Hackers look for information from listening ports and estimate the level of permission that is required to enumerate this information. They also want to know if a login is required to determine if someone has enumerated this information. Hackers also look to see if a potential exists for an authenticated user to view security-sensitive data or personally identified information that might compromise privacy concerns. Hackers can use some of the tools listed here. All of these tools are readily available to download, and security staff should know how these tools work.