Avast distributes widely used free Windows utility called CCleaner. The installer for the utility also installed a malicious payload that was designed to allow attackers to push additional malware onto infected PCs. Avast has publicly confirmed the security problem in a blog post and issued new, clean versions of the utility. The actual number of users affected by this incident was 2.27 million, write Avast CEO Vince Steckler and Ondej Vlek, executive vice president and general manager of Avast’s consumer business.”]
Source: https://www.inforisktoday.com/avast-distributed-trojanized-ccleaner-windows-utility-a-10298