Hum I'm not 100% sure

but I remember that Kaspersky stopped wannacry attack via "Network Attack Blocker" module...
You're probably right about Kaspersky beause Eset did the same too.
"Fortunately, ESET clients were already protected by ESET’s network protection module. This had been blocking attempts to exploit the leaked vulnerability at the network level well before this particular malware was even created. On Friday, ESET increased the protection level for this specific threat via the
Win32/Filecoder.WannaCryptor.D update to the detection engine (
15404, May-12-2017, 13:20 UTC/GMT +02:00). Prior to that, ESET LiveGrid had begun protecting against this particular attack starting around 11:26AM (UTC/GMT +02:00). "