Warning against 'botnet' crime wave
Hackers taking control of computers for extortion and junk e-mails, police say
Police computer experts have warned that hackers who gain control of computers en masse are becoming an international problem and preventing such acts in Hong Kong will be a priority this year.
Hackers can take control of tens of thousands of computers by infecting them with viruses or other programmes and set up what is called a 'botnet' - a network of zombie computers that they can use for crime such as extortion or sending out junk e-mails.
The police said the problem first surfaced overseas last year.
'There had been cases overseas where people would use botnets to engage in blackmailing acts, such as targeting commercial websites and demanding payments from the owners,' said Superintendent Patrick Lam Cheuk-ping, of the Technology Crime Division.
In one of the biggest cases, police in the Netherlands arrested three people in October for building a worldwide zombie network involving more than 100,000 PCs and using it to launch internet attacks on companies as well as hacking into accounts of banks and the internet cash transfer system known as Paypal.
Hong Kong police launched a major internet sweep in November. They found 50 computers in the city had been infected and had become part of overseas botnets.
But they did not find anyone here creating their own zombie network.
Mr Lam said when a computer had been taken over it would become slower than usual. The user may also see e-mails they had not sent but bearing their names being bounced back - a sign that the computer was being used to send junk e-mails.
He said computer owners can protect their machines by:
Installing anti-virus programmes and keeping them updated;
Deleting any incoming e-mails that look dubious;
Refraining from visiting suspicious websites, and;
Ensuring their computer's operating system has the necessary security patches installed.
'If the criminals can use technology [to conduct crimes] then we can use technology to catch them,' Mr Lam said.