A new generation of 'online hoodies' is wreaking havoc in cyberspace, Internet security experts are warning.
The hackers, some as young as 12, begin by phishing for identities on social networking sites before graduating to stealing cash from PayPal accounts. Their scams are believed to be raking in thousands of pounds.
Some even post step-by-step guides on how to pull off the scams - although these are often just another attempt to get money from gullible copycats.
They see themselves as stars and want to boast about their exploits, with one selling T-shirts bearing his online name and proclaiming himself 'the greatest hacker of all time'.
Web security expert Maksym Schipka, whose wife's professional site was defaced, said: 'They know more than we do, they can do more than we can, they understand it better.'
The young hackers are said to be growing increasingly sophisticated.
'There's now a whole sub-industry where people will supply these kids with custom-made tools to create phishing pages to steal bank details,' said web expert Chris Boyd.
Many of the perpetrators boast about what they do on video sharing sites such as YouTube.
Mr Boyd, of internet security firm, FaceTime, added: 'One 12-year-old kid ran a huge forum with thousands of users sharing tips on stealing credit card details and bank details.'
The government concedes online crime is a growing problem and next spring a £7million police unit starts work to combat the latest trend.
But a Home Office spokesman said the 'age of perpetrators isn't an issue'.