Spoofing

Spoofing involves attempting to hide a true identity by using someone else's e-mail or IP address. For instance, a spoofed e-mail will have a forged sender e-mail address designed to mislead the receiver about who sent the e-mail. IP spoofing involves the creation of TCP/IP packets that use someone else's source IP address, indicating that the packets are coming from a trusted host. Most current routers and firewalls can offer protection against IP spoofing.

Spoofing a website sometimes involves pharming — automatically redirecting a web link to an address different from the intended one, with the site masquerading as the intended destination. Links that are designed to lead to one site can be reset to send users to a totally unrelated site — one that benefits the hacker. Pharming threatens the integrity of a site because customers can be redirected to fake sites that look almost exactly like the true site.

Although spoofing and pharming do not directly damage files or network servers, they threaten the integrity of a site. If hackers redirect customers to a fake website that looks almost exactly like the true site, they can collect and process orders, effectively stealing business from the true site. Or, if the intent is to disrupt rather than steal, hackers can alter orders — inflating them or changing products ordered — and then send them on to the true site for processing and delivery.

In addition to threatening integrity, spoofing also threatens authenticity by making it difficult to discern the true sender of a message. Spam (junk) websites (also called link farms) are a related but different threat. These are sites that promise to offer some product or service, but in fact are just a collection of advertisements for other sites, some of which contain malicious code. These sites cloak their identities by using domain names similar to legitimate firm names.