A hacker usually uses a proxy server -

A hacker usually uses a proxy server to hide malicious activity on the network.
The attacker creates a copy of the targeted web page on a proxy server and uses methods such as keyword stuffing and linking to the copied page from external sites to artificially raise its search engine ranking.
The authentic page will rank lower and may be seen as duplicated content, in which case a search engine may remove it from its index.
An attacker may use a proxy server to gain an advantage over a competitor or, ultimately, to redirect users requesting the targeted page to a malicious or fraudulent website.