Security threats that try to steal confidential information or compromise IT systems continued to increase during the last six months of 2004, according to the latest Internet Security Threat Report from security vendor Symantec Corp. Businesses suffered an average of 13.6 attacks per day in the second half of last year, up from 10.6 daily attacks in the first six months of the year, the report says. And there were 1,403 new vulnerabilities discovered during that period, a 13% increase from the previous six months.

Symantec says malicious code designed to expose confidential information made up more than half all code samples picked up by the vendor. And Trojan horses by themselves made up a third of all the malicious code.

Phishing, the report says, continues to be a major problem, and the threat is growing. Symantec last July blocked around 9 million phishing incidents per week. By December, the amount grew to around 33 million per week. Symantec says its Brightmail AntiSpam software blocked most of those attempts.

Symantec says Slammer, or the Microsoft SQL Server Resolution Service Stack Overflow Attack, was still the most common kind of security attack seen. And financial-services companies faced more serious attacks than other companies, experiencing around 16 severe events for every 10,000 security events.