Microsoft today released the fifth volume of its Security Intelligence Report, providing insight into the security and privacy threat landscape in the January – June 2008 period. The statistics revealed that in the first half of the year, the total amount of malware and potentially unwanted software removed from computers worldwide increased at an alarming rate, reaching 43 percents over the second half of last year.

Furthermore, infection rates were found to be higher in developing countries than in developed countries, but at the same time, the rates also decreased in computers using higher service pack levels, a trend Microsoft said can be observed consistently across client and server operating systems half-year period over half-year period.

The report also revealed that over 50 percent of the spam messages filling e-mail addresses contained advertisements for pharmaceutical products, more than half of which were Viagra and Cialis advertisements.

Microsoft also found that despite the fact that U.S.-based financial institutions are the most targeted by phishing attempts, the trend began to move towards other English-speaking countries, such as the United Kingdom and India.

Geographically speaking, the report reveals differences in threats in different parts of the world. For example, while in Brazil password stealers are the most common threat, Chinese users are dominated by potentially unwanted software, namely pop-up advertisement toolbars and browser modifiers.

In Korea on the other hand, viruses represent the largest category of threat, and they are usually spread through P2P networks file-sharing community sites. In the United States, Trojan downloaders represent the highest threat, while in Spain, worms are unusually common.

Regarding the security on Windows operating systems, Microsoft said the rates of infection are differentiated according to the OS versions. One plus for Microsoft Vista is that compared to its predecessors, it offers a lower rate of infection (85.4 percent less than in Windows XP).