Here is the New York Times story on the latest ransomware attack, called “Petya”, which seemed to spread quickly from the Ukraine this morning It is also related to a malware scheme called “eternal blue”.
So far, a few American companies, including pharmaceuticals and one law firm, and smaller hospitals have been affected.
Trend Micro has a detailed writeup as of 12:30 PM today.
Heavy.com has a detailed story.
It is not clear if users who had installed previous Microsoft vulnerability patches are protected.
It is not clear if the latest Microsoft systems are less vulnerable. It also spreads through Port 445 (for Microsoft shares). This virus seems to affect master boot records rather than encrypting files.
The Microsoft page published today June 27 says that Windows Defender Antivirus removes the threat so it should not be hard for all antivirus companies to do this.
Malware Tech has a good explanation that novices can understand, here.