Explainer: what is hacking?

Last week, we woke to news that the largest cyber attack ever was underway in Europe, with reports of global internet speeds falling as a result of an assault on the anti-spamming company Spamhaus. In recent weeks, the Reserve Bank of Australia has been the target of a cyber attack, as have South Korean banks and broadcasters and BBC Twitter accounts. The above stories were all reported as "hacking" - a blanket term readily used to encompass a whole range of attacks, from crashing a server to more sophisticated infiltration, such as stealing passwords. But, generally, news stories don’t discriminate. So what are hackers and their methods really like? What follows is something of a glossary, to cut out (or at least bookmark) and keep.