Ransomware known as Black Kingdom demands $10,000 for the recovery of encrypted data. The malware is getting installed on Exchange servers that were previously infected by attackers exploiting a critical vulnerability in the Microsoft email program. Attacks started while the vulnerability was still a zeroday. Even after Microsoft issued an emergency patch, as many as 100,000 servers that didn’t install it in time were infected. The number of vulnerable servers in the US dropped to less than 10,000, according to Politico.