“The best that officials in Plainfield, N.J., can tell, the hackers got in when someone was on the Internet researching grants, and soon employees in the mayor’s office were locked out of their own files. City officials scrambled to pull servers offline, but three had been compromised, leaving memos, city newsletters and other documents inaccessible.”
Source: These hackers can hold a town hostage. And they want ransom — paid in bitcoin. – The Washington Post