"The number of malicious Web sites has skyrocketed over the past few months, going from 5,000 new ones a day in April to nearly 30,000 a day now.
"This certainly is a huge increase," said Carole Theriault, a senior security consultant with Sophos, Inc., in an e-mail to InformationWeek. "In June, we saw it climb to 9,500 a day and then this huge jump up 29,000."
"The IFrame malware was a major Web site infector in June.
IFrame, which injects malicious HTML files onto Web pages, actually topped Sophos' chart for June's Top 10 Web Threats, accounting for nearly two-thirds of the world's infected Web pages. Earlier this month, hackers used the IFrame to attack multiple Italian Web sites. Sophos reported that more than 10,000 Web pages were infected in the attack, most of which were on compromised legitimate sites hosted in Italy. Victim Web sites included Italian city councils, employment services and tourism sites. Most of the affected pages appear to be hosted by one of the largest ISPs in Italy, noted Sophos. "