Another piece of Malicious adware called the Efast Browser has come to light over the last few months. It does all the usual nasty things associated to Adware such as launching pop-up ads and under ads on your screen, bombarding your web pages with additional ads pushing you to other websites that have more malware and Making sure that your movements are tracked ensuring other marketers can send you more adverts.
What this malware also does unlike other Malicious adware is replace your browser. Efast as it is known basically tries to replace Chrome by hijacking as many link and file associations as it possibly can. This adware basically tries to install a new browser rather than hijacking your existing browser.