Cisco’s TALOS security researchers discovered a devious way to infect millions of machines. They said: “Supply chain attacks are a very effective way to distribute malicious software into target organizations. This is because with supply chain attacks, the attackers are relying on the trust relationship between a manufacturer or supplier and a customer. This trust relationship is then abused to attack organizations and individuals and may be performed for a number of different reasons.”

https://blog.knowbe4.com/the-ccleaner-app-designed-for-good-cyber-hygiene-was-itself-infected-with-a-backdoor