Age: 58

The hacker known as "ASTRA" was never publicly identified, but is said to have been a 58-year-old mathematician when he was arrested in 2008. Greek authorities said that he hacked into the systems of the aviation company, Dassault Group, for about half a decade. In that time, he stole weapons technology information about the company's jet fighters and other military aircraft, and sold it to different countries. It's said that he sold this data to nearly 250 people in the Middle East, Brazil, France, Germany, Italy, and South Africa, all for $1,000 a pop. The damages to Dassault amounted to more than $360 million.