Pharming (pronounce farming) is a hacker's attack aiming to redirect a website's traffic to another, bogus website. 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 addresses — they are the "signposts" of the Internet. Compromised DNS servers are sometimes referred to as "poisoned". The term pharming is a word play on farming and phishing. The term phishing refers to social engineering attacks to obtain access credentials such as user names and passwords. In recent years both pharming and phishing have been used to steal identity information. Pharming has become of 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.