The number of spam sent per month back in July 2010 used to be around 90 billion. In a year’s time, this number has been brought down to just 25 billion. This is one of the revelations made in Microsoft’s latest Security Intelligence Report. Click on the right arrow on the top of the article to see how this was achieved.
In August 2010, a major botnet called Cutwail was shut down. By March 2011, another botnet named Rustock – famous for having sent up to 30 billion spam emails a day – got taken down after more than two months of dormancy. Microsoft says the shut down of these two botnets – automated software that hold infected computers hostage to send spam from these computers – alone has contributed to such drastic drop in numbers.
This operation is being carried out by Microsoft’s inhouse Digital Crimes team in partnership with anti-virus programmers like Kaspersky labs. One of their latest catch was the Kelihos botnet that controlled more than 41,000 computers worldwide that sent out close to 4 billion spam messages every single day! This is how the numbers have come down in the past one year.
So what are the most popular categories of spam sent through emails? The Microsoft study shows that over 13% of the emails were scams. Another 4.8% were phishing related messages and another 2.5% were ‘get rich quick’ schemes. The majority of the messages – over one fourth of them – were in the “Pharmacy – Non sexual” category.