The percentage of threats arriving in email that rely on links to malicious sites — rather than arriving as a file attachment — has ballooned 10-fold since the first quarter of the year, says a security company.
In a report published last week, UK-based MessageLabs said that 35% of the email threats it now detects use embedded links to infect computers instead of the more traditional file attachments. In the March-June time frame, that figure was 20.2%, said the company. And in the opening quarter of 2007, a mere 3.3% of the intercepted threats carried links.
MessageLabs' data jibes with recent analyses by other security vendors, which have all noted the rapid increase in web-based attacks — often from legitimate sites that have been compromised by criminals. Such trusted sites make perfect lures for drawing in users, whose browsers are then typically attacked through one or more unpatched vulnerabilities, allowing rogue code — often spyware or a Trojan horse that hijacks the PC to add it to a growing botnet — to be installed.
"The bad guys know that most people have learned not to open attachments," said Wood. "Email is still the preferred attacker vehicle for getting their 'message' across, but now they're using links. They know people still follow links."