Rustock Botnet Responsible For Majority Of Spam
Posted by Mike Sachoff
Symantec has released its April 2010 MessageLabs Intelligence report, which found that Rustock has surpassed Cutwail as the biggest botnet both in terms of the amount of spam it sends and the amount of active bots under it control.
While Rustock has reduced the output of individual bots by 65 percent, it has increased the number of active bots by 300 percent, making up for the decreased output. Meanwhile, Cutwail has reduced in size to 600,000 bots down from 2 million bots in May 2009 and is now responsible for only 4 percent of all spam. Rustock remains the largest spam-sending botnet responsible for 32.8 percent of all spam.
“Affected by the closure of ISP Real Host in August 2009, Cutwail likely lost the ability to update some of its bots causing its numbers to diminish greatly without the ability to recover,” said MessageLabs Intelligence Senior Analyst, Paul Wood.
“As a result, Rustock has taken over significant volumes from spammers by undercutting the market with greater capacity and lower operational costs.”
Also in April, MessageLabs Intelligence analyzed passive fingerprinting (PF) signatures of spam email traffic to learn the types of operating systems that were running on the infected spam-sending computers. Many of the infected machines were running Windows and the percentage of spam with a PF signature was similar to the Windows share of the operating system market.
“Spam is more commonly sent from computers running Windows than from those running other operating systems,” Wood said. “However, spam not identified as coming from botnets was seen in lower proportions coming from Windows machines than from known botnets.”
About the Author: Mike is a staff writer for WebProNews. Visit WebProNews for the latest ebusiness news.
Leave a Reply