If you'd downloaded CCleaner between August 15 and September 12 it's infected with Malware:
In an email to Bleeping Computer, Avast CTO Ondrej Vlcek said that updating CCleaner to the most recent recent versions fixes any issues, as "the only malware to remove is the one embedded in the CCleaner binary itself."
"The affected software (CCleaner v5.33.6162 and CCleaner Cloud v1.07.3191) has been installed on 2.27M machines from its inception up until now," Vlcek also added. "We believe that these users are safe now as our investigation indicates we were able to disarm the threat before it was able to do any harm."
"There is no indication or evidence that any additional "malware" has been delivered through the backdoor," Vlcek added.
https://www.bleepingcomputer.com/new...lmost-a-month/
PSA - CCleaner was infected with malware between August 15 and September 12
