The pharming attack definition, according to Wikipedia: “Pharming is an attacker’s attack intended to redirect a website’s traffic to another, bogus site. Pharming can be conducted either by changing the hosts file on a victim’s computer or by exploitation of a vulnerability in DNS server software. DNS servers are computers responsible for resolving Internet names into their real IP addresses. Compromised DNS servers are sometimes referred to as “poisoned.” Pharming requires unprotected access to target a computer, such as altering a customer’s home computer, rather than a corporate business server.
The term “pharming” is a neologism based on the words “farming” and “phishing.” Phishing is a type of social-engineering attack to obtain access credentials, such as user names and passwords. In recent years, both pharming and phishing have been used to gain information for online identity theft. Pharming has become a major concern to businesses hosting ecommerce and online banking websites. Sophisticated measures known as anti-pharming are required to protect against this serious threat. Antivirus software and spyware removal software cannot protect against pharming.
A pharming attack will redirect the victim to the fake website (an attacker website) even though the victim enters the correct address for the legitimate website. For Example: The victim intends to access www.twitter.com, so he writes the right URL to the browser, the URL will still be www.twitter.com, but he will surf the fake website instead.