Australia's Bureau of Meteorology was recently hacked. While that may seem innocuous to some, it can present big-time problems for others. Many people and entities rely on accurate weather to safely do their jobs, to include my chosen field--aviation. How dangerous would it be for an airliner to assume the forecast provided permitted a safe flight to their destination? How exactly it was hacked hasn't been ascertained, but it has been revealed it will take upwards of a year and hundreds of millions of dollars to fix.
http://www.bbc.com/news/world-australia-34980884