1) Pharming is a scamming practice in which malicious code is installed on a personal computer or server, misdirecting users to fraudulent Web sites without their knowledge or consent. Pharming has been called "phishing without a lure."

In phishing, the perpetrator sends out legitimate-looking e-mails, appearing to come from some of the Web's most popular sites, in an effort to obtain personal and financial information from individual recipients. But in pharming, larger numbers of computer users can be victimized because it is not necessary to target individuals one by one and no conscious action is required on the part of the victim. In one form of pharming attack, code sent in an e-mail modifies local host files on a personal computer. The host files convert URLs into the number strings that the computer uses to access Web sites. A computer with a compromised host file will go to the fake Web site even if a user types in the correct Internet address or clicks on an affected bookmark entry. Some spyware removal programs can correct the corruption, but it frequently recurs unless the user changes browsing habits.

A particularly ominous pharming tactic is known as domain name system poisoning (DNS poisoning), in which the domain name system table in a server is modified so that someone who thinks they are accessing legitimate Web sites is actually directed toward fraudulent ones. In this method of pharming, individual personal computer host files need not be corrupted. Instead, the problem occurs in the DNS server, which handles thousands or millions of Internet users' requests for URLs. Victims end up at the bogus site without any visible indicator of a discrepancy. Spyware removal programs cannot deal with this type of pharming because nothing need be technically wrong with the end users' computers.

Once personal information such as a credit card number, bank account number, or password has been entered at a fraudulent Web site, criminals have the information and identity theft can be the end result.

2) Another form of pharming, known as gene pharming (unrelated to the Internet form of pharming) is a biotechnological process in which the DNA of an animal is altered so the animal produces human proteins for pharmaceutical use. The proteins appear in the blood, eggs, or milk of the animal. This has been done with livestock to produce several useful drugs.

This was last updated in June 2007

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