The problem

Many organizations compete among themselves to get their sites at the top of search engine result pages. It is a hard fight for a valuable resource.

Some of them may not be concerned about the means, using BlackSEO techniques like SPAM in collaborative or social sites and unauthorized modifications of other website contents. In particular, this uses to happen when the promoted pages are ilegal or don't fully comply with all applicable laws.

Why do they do that? Because they think that they need to have a lot of links pointing to their websites. Links can be used by search engines to determine how popular, or how relevant, a site is. The idea is "the higher the number of links, the better position you may get". Not fully correct, but easy to understand an conceive.

So they find vulnerable sites and modify them, inserting text and links.

In these scenarios, attackers may have a couple of concurrent goals:

• • Unauthorized modifications must be visible to search engines.

  • Unauthorized modifications must go unnoticed by Webmasters and site owners as long as possible, so that they don't delete them.

  • Users looking for the products they sell must get links to the promoted pages or be redirected to them.

Next: How do they do it?