The REvil ransomware gang’s attack on MSPs and their customers last week should have been successful, yet changes in their typical tactics and procedures have led to few ransom payments. The attack is likely not nearly as successful as the REvil gang would have expected. The gang used a zero-day vulnerability in on-premise Kaseya’s VSA servers to perform a massive and widespread attack without actually accessing a victim’s network. This tactic led to the most significant ransomware attack in history, with approximately 1,500 individual businesses encrypted in a single attack.
Source: https://www.bleepingcomputer.com/news/security/revil-victims-are-refusing-to-pay-after-flawed-kaseya-ransomware-attack/