Cyber criminals who stage attacks on computers and computer networks are moving from hacking for fame to hacking for financial gain, a conference organised by US computer security company Symantec has been told.

Stolen details of British credit cards can now be bought over the internet for as little as $4 (€3), while US credit card details can be obtained for $2, according to Symantec, which scans up 30 per cent of the world's e-mail traffic.

A complete identity - including a name, driver's licence number or other form of government identification and credit card numbers - can be obtained for $14, the company claims.

Much of the data is gleaned via "phishing" e-mails which attempt to lure individuals to decoy websites that appear to be legitimate banks or online services and getting them to enter their account numbers, credit card numbers and passwords.

Symantec said that in the second half of 2006 it logged more than 1.5 billion unique phishing sites and saw more than 900 sites created daily. Most of these only exist for hours or days before moving on or being closed down, making it difficult for the law to capture those involved.

Symantec put much of the explosion in data theft down to a change in the nature of hacking.

"Before, hackers hacked for fame, today it's for financial gain," according to a briefing on cyber crime given this week at the company's annual Vision conference in Las Vegas.

Now cyber criminals want to remain unknown and to operate secretly. The goal is data theft, data leakage and installing malicious codes on the computers of unsuspecting users that will either capture personal information or allow hackers to remotely use the computer for further attacks.

Often, such "botnets" of computers are hired by criminal gangs, Symantec claims. China has rocketed up the botnet league table, jumping from sixth to second place in recent months. The UK is in first place.