In the early days of the Internet, geeky hackers competed to see who could create the most diabolical computer viruses. The motivation was a twisted kind of bragging rights. But a study released by IBM says hackers today have a different motivation -- profit.

In its Global Business Security Index, the computer giant says email continues to grow as a security menace, with messages often disguised as communications from legitimate entities that seek to pry personal and financial information from the unsuspecting. Believed to be largely driven by criminal gangs, phishing was tied to 35.7 million emails in the first half of 2005.

The experts also noted an increase in spear phishing, highly targeted and coordinated attacks at a specific organization or individual designed to extract critical data. Also, more and more electronic messages contain viruses that can harm computer or network operations.

The overall volume of viruses has exploded. In January of 2004, one in every 129 emails contained a virus; by June of this year, infections had spread to one in every 28 emails.

The first half of 2005 saw more than 237 million security attacks overall, more than 20 percent of which were aimed at government computers. The United States was overwhelmingly the target location for attacks (12 million), followed distantly by New Zealand (1.2 million) and China (1 million).

Surprisingly, spam, unsolicited and unwanted email, provided a bright spot in the study. The ratio of spam to legitimate email continuously decreased over the course of the last six months, from 83 percent in January to 67 percent in June 2005.

"IBM advises its clients to rapidly adopt a holistic, enterprise-wide approach to security and risk management," said John Lutz, general manager of IBMs Financial Services Sector.