Weknow.ac is search engine redirect and browser hijacker, that attacks Safari, Google Chrome, Mozilla Firefox. Website is set up as homepage, new tab and default search engine. However, user search queries are redirected to webcrawler.com, which is known browser hijacker. Weknow.ac is often accompanied by browser extensions, that controls settings and can have random name. Having potentially unwanted add-on, can be dangerous for privacy as hijacker collects browser data and use it for commercial purposes.