Today (9/20/17) I received an update pop-up, allegedly from CCleaner that a new, important update was available. When I said go ahead, an update proceeded immediately. I got a message that this was an "unusual" download and might not be safe. Uninstalled and erased everything followed by a security scan. Nothing found. If I get the pop-up again, for CCleaner 3.535, I post the image.
TLin Maine
*** Re-installed CCleaner 5.34 and immediately got the "important update" notice. Screen capture attached.