DEFAULT-SEARCH.NET is a browser redirect program that can be risky when installed on the computer. This adware can replace home page with unknown search engine. If you are seeing DEFAULT-SEARCH.NET as part of the browser, it only confirms that it is compromised. Browser hijacking intends to replace your search engine so that it can display ads on home page as well as search results. This can generate revenue for adware authors. However, users have nothing to gain aside from being annoyed by too much display of advertisements. For that ground, many users deemed DEFAULT-SEARCH.NET as part of virus activity.
How To Remove DEFAULT-SEARCH.NET