As we, here at Softpedia, told you back in April, Srizbi is the world's largest botnet ever. Following its evolution, which is also known as Cbeplay and Exchanger, Marshal, one of the global leaders in Email and Internet Content Security, just announced that Srizbi accounts for half of the world's spam. A press release dated May 8 states that this botnet has had a considerable growth over the last two months.

Since April, Srizbi has been reported by SecureWork to be the most dangerous botnet ever found loose on the web. The rookit-enabled botnet is said to send 60 billion spams per day, using no less than 300,000 compromised computers. The numbers that make up Srizbi are dangerously impressive and have prompted security companies all over the world turn their attention towards solving this issue. According to Symantec, Trojan.Srizbi hides itself as a rootkit and operates completely within the kernel.

It appears that the giant Srizbi has surfaced to take the place of the Mega-D botnet, after its control servers have reportedly been taken down for 10 days. According to Marshal, Srizbi is been said to recently promote pens, watches and other products while actively distributing copies of its malware.

Microsoft is yet far from finding a solution to the Srizbi botnet, as it recently announced it had successfully succeeded in combating the Storm Botnet with their Malicious Software Removal Tool. The Storm Botnet was the major web threat back in January this year. However, compared to the current number one, its numbers featured a total of only 3 billion spams per day.

At this point, the number one leader, Srizbi, makes for 49.4 percent of the total world spam, followed by Mega-D with only 17.3 percent and Rustock with 15 percent. The numbers clearly indicate that Srizbi is by far the world's biggest web threat.