Browser malware infection is rare, however. The reason can range from something as benign as a browser extension and unwanted software to dangerous malware and browser hijacking. You might also notice more ads, pop-ups, odd search results, or unwanted toolbars. You set the default to Google again, only to find out it's been changed back to Bing, seemingly on its own. Say, it redirects your search queries to Bing.
But sometimes, the default search engine will change on its own.
