SEO Poisoning

Search engines such as Google work by ranking pages and presenting relevant results based on users’ search queries. Depending on the relevancy of web site content, it may appear higher or lower in the search result list. SEO, short for Search Engine Optimization, is a set of techniques used to improve a website’s ranking by a search engine. While many legitimate companies specialize in optimizing websites to better position them, a malicious user could use SEO to make a malicious website appear higher in search results. This technique is called SEO poisoning.
The most common goal of SEO poisoning is to increase traffic to malicious sites that may host malware or perform social engineering. To force a malicious site to rank higher in search results, attackers take advantage of popular search terms.