Online Security

Attackers bent on shutting down large Web sites -- even the operators that run the backbone of the Internet -- are arming themselves with what are effectively vast digital fire hoses capable of overwhelming the world's largest networks, according to a new report on online security.

In these attacks, computer networks are hijacked to form so-called botnets that spray random packets of data in huge streams over the Internet. The deluge of data is meant to bring down Web sites and entire corporate networks.

On Tuesday, Yahoo and McAfee announced a partnership to make the Yahoo Search experience safer. Launched in beta, the new SearchScan feature, powered by McAfee SiteAdvisor technology, offers always-on alerts for sites with security concerns involving spyware, adware and other malicious software. McAfee SiteAdvisor tests and rates nearly every trafficked site on the Internet.