The number of internet domains serving up ransomware has risen massively in just the space of three months, as cybercriminals look to cash in. Sites designed to host malware, exploit kits, phishing scams, and other threats have also reached their highest-ever level, according to security researchers at Infoblox. In raw numbers, exploit kits remain the biggest security threat, accounting for just over 50 percent of the index. As in past quarters, Angler remains the top piece of ransomware, but a new contender has emerged from far back in the pack: observations of Neutrino have grown by 300 percent, the researchers said. “Again in simple terms: Ransomware is working,” the report said.