A German hacker generated more than $620,000 in cryptocurrency after hijacking an unknown number of network storage devices and turning them into digital slaves to mine Dogecoin, researchers say. Hackers have long targeted cryptocurrency with specialized malware, but almost all of their efforts have targeted existing digital money, primarily Bitcoins, stored in virtual “wallets” Hackers could easily modify their code to be more surreptitious, making it harder for victims to notice that their machines were secretly working on someone else’s behalf.”]