As if zombie PCs -- computers taken over by hackers and used to distribute spam and malware -- weren't already bad enough, they are now harder to prevent than ever before.That's because they're getting smarter and harder to track down, according to security software vendor Commtouch. New zombies now routinely request new IP addresses from their ISPs, so anti-spam software that works by blocking spam based the originating IP addresses can no longer effectively halt them, the company said in its most recent quarterly Internet Threats Trend Report.

Significant growth in user-generated content has led to new Internet security threats, according to a new report by Commtouch.
The report found streaming media and downloads are among the top 10 Web site categories infected with malware and /or manipulated by phishing. These are two of the most popular categories within user generated content sites.