Definition for "PHARMING"
(source :
wikipedia)
Pharming is the exploitation of a vulnerability in the DNS server software that allows a cracker to acquire the Domain name for a site, and to redirect, for instance, that website's traffic to another web site. DNS servers are the machines responsible for resolving internet names into their real addresses - the "signposts" of the internet. The term pharming is derived from the term phishing, the use of a social engineering attack to obtain access credentials such as usernames and passwords. To date however the use of pharming to perform Internet crime for profit has not been demonstrated.
Explanation of pharming
Every host on the Internet has a so-called IP Address which consists of four numbers, each between 0 and 255, which are separated by . (dots), for example "192.0.2.213". These IP Addresses are comparable to the telephone numbers on a telephone system. As it would be very difficult to remember these numbers, websites usually also have a domain name, for example "wikipedia.org". The domain name server acts as a "phone book" to associate the domain name of a website with its IP Address ("resolving the domain name").
If the web site receiving the traffic is a fake web site, such as a copy of a bank's website, it can be used to "phish" or steal a computer user's passwords, PIN number or account number. Note that this is only possible when the original site wasn't SSL protected, or when the user is ignoring warnings about invalid server certificates.
For example, in January 2005, the Domain Name for a large New York ISP, Panix, was hijacked to a site in Australia.
Secure e-mail provider Hushmail was also caught by this attack on 24th of April 2005 when the attacker rang up the domain registrar and gained enough information to redirect users to a defaced webpage.