Businesses are under more threat than ever from computer hackers, an internet service provider has warned.

These findings are a wake-up call to anyone who thought their website or servers were safe from hackers UK Managing Director of PSINet Europe

In a test, a "dummy" server set up by PSInet Europe was attacked by hackers nearly 500 times in a 24 hour period.

The cyber-criminals scanned the system for weaknesses and made repeated unauthorised attempts to break in.

Over a three week test period, PSInet discovered 60 individuals around the world persistently attempting to breach the unadvertised server's security.

The company says the test illustrates the danger lurking on the internet for unsuspecting firms.

Worst attack

PSInet's warning follows one of the most virulent attacks yet seen on the world wide web.

The worm known as SQL Slammer targeted a known weakness in Microsoft's database software, over the weekend.

At its peak, experts said the worm affected around a quarter of a million computers worldwide, with the world's most wired country, South Korea, being one of the worst affected.

Firms aren't doing enough to protect themselves Stephen Scott, UK PSInet managing director

Several UK firms, including Hewlett Packard, Borders.co.uk, Letsbuyit.co.uk and Thorntons.co.uk were also affected.

'No holidays'

In its test, PSInet's anonymous server registered a total of 626 malicious attacks.

The company found:

• A high number of attacks originate from broadband or cable ISPs
• Most attacks originated in the US and Western Europe
• Countries often associated with attackers, such as Russia, Bulgaria and Romania did not feature

Stephen Scott, UK Managing Director of PSINet Europe, said: "These findings are a wake-up call to anyone who thought their website or servers were safe from hackers.

"Our dummy server should by rights have sat in splendid isolation in the Data Centre - with no connections, scans or attacks expected.

"Instead we found that nearly 500 intrusions were attempted on day one of its installation.

"This, added to the fact that hackers clearly don't take holidays - as the number of Christmas attacks demonstrates."

"The findings underlined the need for proper security for companies' web sites," he added.

"The issue here is not just that firms aren't doing enough to protect themselves, but also that they are not spending enough time analysing exactly what the threat is to their online presence, and what security measures would best serve to protect them."