The functionality of Ramsonware in relation to extension networks
"WannaCry is a so-called crypto-worm, which means that the malware uses cryptographic methods to encrypt the data of the infected system and at the same time spreads "worm-like" and infects networked components. To accomplish this, the malware first established a base of operations on a Windows system in the network by exploiting the vulnerability CVE-2017-0144." -www.sichere-industrie.de