"As soon as we learned of this problem, we immediately moved to find a solution and managed to overcome it.Within 72 hours the problem has been solved and we want to report that so far no customers are negatively affected by the backdoor that can be a door enter the malware, "wrote the Avast through its official blog.
CCleaner is an application created by Piriform that has been acquired by Avast on July 18, 2017 yesterday. Avast Party said hackers have been targeting Piriform internal server since before Avast acquired the company.
While an infected version of CCleaner was released on August 15, 2017 and continues to be undetected by the system for four weeks.
Avast first noticed an infection in CCleaner on September 12 through a company called Morphisec who also told Cisco.
Avast Party is said to immediately conduct an investigation so that the cause can be immediately immediately known.
So far only CCleaner versions of 32-bit and 64-bit Windows are infected. Avast Party has released an update and notify all users. Unfortunately, users of the free version must update manually because the automatic update feature is only for paid subscribers.