More than 97% of all emails sent worldwide are unsolicited spam messages, according to research by Microsoft.

Unsolicited emails advertising drugs, sales messages or various forms of malware make up an overwhelming majority of email messages as hackers take a different approach to online crime.

Instead of looking to exploit holes within operating systems, a practice which is becoming increasingly preventable through advancements in security software, hackers now preferring to hide malicious software, including adware or spyware, in common file format attachments such as Microsoft Office or PDF files.

The belief is that as antivirus software becomes more sophisticated, hackers are increasingly considering the “weak link” in PC security to be the human elements.

Ed Gibson, chief cyber security advisor at Microsoft, said the rise in spam was due to traditional organised crime figures moving away from exploiting software vulnerabilities and “targeting the weak link that is you and me”.

“With higher capacity broadband and better OS (operating systems), and higher power computers it is easier now to send out billions of spams. Three or four years ago the capacity wasn’t there.”

The report, which studied online activity during the second half of 2008, also pinpoints the countries that are suffering from the most infections of computer viruses, with Brazil and Russia dubbed as the most “infected” countries. Computers in Turkey and Serbia and Montenegro were also considered to most at risk.

The company also revealed that the type of virus or malware that users were likely to be affected by depended heavily on the country or region that they were in.

In China, several malicious web browser modifiers are common, while in Brazil, malware that targets users of online banks is more widespread. Computers in Korea were more likely to be hit with viruses such as Win32/Virut and Win32/Parite.

“As the malware ecosystem becomes more reliant on social engineering, threats worldwide have become more dependent on language and cultural factors,” said the report.

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