Neutrino EK now includes fingerprinting of the user’s machine. The purpose of fingerprinting in the case of exploit kits or malvertising campaigns is to avoid unnecessary attention by checking for undesirable users (researchers, honeypots, etc) and not serving them the exploits and malware payload. The strange thing with this particular fingerprinting is that the victim is most likely genuine since they are not using monitoring tools or testing the exploit kit inside of a Virtual Machine, therefore making them a good candidate for the exploitation and infection phases that follow up.”]
Source: https://blog.malwarebytes.com/cybercrime/exploits/2016/06/neutrino-ek-fingerprinting-in-a-flash/