BOSTON -- IT security and control firm Sophos has reported a dramatic decrease in the amount of spam emails using PDF file attachments to spread their unwanted messages. According to research compiled by SophosLabs, Sophos's global network of virus, spyware and spam analysis centers, levels of PDF spam have dropped from a high of close to 30 percent of all spam earlier this month to virtually zero.

"Although PDF spam is showing a decrease currently, there’s no reason to believe that it will not strike again,” said Ron O’Brien, Sophos’s Boston-based senior security analyst. "Because of the nature of PDF attachments, it takes more time to open this type of file, which could deter people from clicking on it. A malicious embedded link, on the other hand, is quick and easy to access and would probably have a higher likelihood of luring people to open – which could be one reason for the decrease in PDF spam.”

Levels of PDF spam spiked on August 7, 2007, when a single campaign designed to manipulate stock prices of Prime Time Group Inc, accounted for a 30 percent increase in overall junk email levels. Since then, however, PDF spam has shown a sharp decrease.

“Spammers are in this business for one reason – to make money,” continued O’Brien. “If PDF spam isn’t working, they are going to move on to another method of attack. This is why it’s so important to use safe online and email practices at all times when opening or clicking on any type of file or attachment.”

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