A sharp rise in the volume of malicious spam this month can be largely attributed to the Srizbi botnet, according to researchers at Marshal. Spam intended to infect users’ computers with malware tripled in one week, jumping from 3% of total spam at the beginning of June to 9.9% the following week.
The Srizbi botnet currently is spewing out spam that tries to trick users into clicking on a link by including the first part of their email address in the subject line, and the suggestion that they look stupid in a video, according to Marshal. It’s also spoofing the Classmate.com service with emails that include a link to a fake Classmate.com page that instructs them to run a Flash video player. When users click on the link, they’re prompted to download an executable that infects their computers.
Phil Hay, lead threat analyst with Marshal’s TRACE team, called the Srizbi botnet “one of the biggest threats to Internet users today.” Marshal said the botnet is responsible for 46% of all spam.