Attempts by hackers to take advantage of a computer via the World Wide Web are increasing faster than reports of virus infections, according to a new study.

More than 56 percent of organizations surveyed reported web-based attacks during the last year, up from 37 percent the year before, according to the Computing Technology Industry Association, the industry advocacy group that conducted the survey.

Using web pages to infect computers running browsers such as Microsoft’s Internet Explorer has become a recent hacker favorite. Earlier this month, even MSN.com fell victim to such an attack.

Hackers installed malicious code on the popular Korean version of the Microsoft web site. The code took advantage of users who surfed to the site and had not installed the most recent Microsoft updates (See New Clues in MSN Hack).

Microsoft released a patch Tuesday designed to prevent attackers from using Internet Explorer to gain control of a user’s computer. The weakness was a product of the way Microsoft handles its help files, according to eEye Digital Security, which alerted Microsoft to the problem three months ago.

Antivirus Strategies

Traditional security vendors are looking to augment their offerings in light of the emerging trend of web-based attacks.

Trend Micro acquired Kelkea, a “reputation-filtering” company for an undisclosed sum on Tuesday. Kelkea’s technology is currently focused on blocking spam, but might be leveraged into protecting users from Internet attacks.

One type of Internet attack Trend Micro hopes to fight is pharming. In a pharming attack, a hacker exploits a vulnerability in the domain name system, or DNS, to redirect a user to a malicious web site.

Kelkea’s technology assigns a reputation to computers across the globe. If one of those computers regularly hosts malicious sites, Kelkea’s technology will throw up a red flag.

Kelkea also promises to help Internet service providers beat the problem of zombie spam networks, which are groups of hacker-compromised computers that are forced to send email.

The buyout is Trend Micro’s second in two months. The company purchased anti-spyware and anti-adware company Intermute in May.

Despite the rising threat of web-based attacks, the market for antivirus software doesn’t look to be going anywhere.

Corporations and non-profits reported viruses as the No. 1 problem in computer security. Two-thirds of the organizations surveyed in the Industry Association’s study having suffered infections during the last year. That number is down slightly from last year’s result of 68.6 percent of organizations reporting infections.