More than 100 million messages contain attachments that, if opened, install software that takes over computers, security experts say.
More than 300 brands were attacked each month in the first half of 2011.
The number of reported unique phishing attacks in the first half of 2011 reached a peak of 26,402 in March, down 35% from a high of 40,621 in August 2009, the Anti-Phishing Working Group, or APWG, says in a report released last month.
Phishing attacks are efforts by criminals to make an e-mail or web site look like that of legitimate brands to typically try to convince unwitting consumers to click to a phishing site to update their payment account information. Criminals then usually either sell that information to other criminals or use it to conduct fraudulent purchases. The APWG monitors worldwide web site activity to track phishing attacks.
In the first half of 2011, April scored the lowest number of phishing attacks at 20,908, APWG says.
The number of unique phishing web sites reached a peak in last year’s first half of 38,173 in March, down 32% from its peak of 56,362 in August 2009.
In other findings, APWG notes that the U.S. remains the largest source of phishing sites, accounting for 46.42% of those sites in June 2011. Next was Egypt at 10.53%, followed by Germany, Netherlands, the Republic of Korea, Russia, the U.K., France and Brazil.