Rich Search Browser Hijacker
Rich Search is the name of a browser hijacker that can affect your browser of choice.
Browser hijackers are a subcategory of potentially unwanted programs. They will usually install on your system without sufficient disclosure and make changes to your browser's settings without asking for user consent.
In the case of Rich Search, your home page will be changed, as well as the default search engine used by the browser - the one that is used when you type directly into the address bar of the browser.
Browser hijackers like Rich Search can also monitor and store data on your search queries and browsing habits. This data may seem harmless but it can also be re-sold to third parties, usually advertising companies.
Removing any sort of browser hijacker found on your system is always the right thing to do. Usually, similar hijackers come in the form of browser extensions that can be removed from the browser's menu. In rare cases, they may have persistence mechanisms and require the use of a dedicated anti-malware application to clean completely.