Microsoft calls in FBI after hacker attack
Microsoft has called in the FBI after hackers blocked access to several of its websites.
The so-called "denial-of-service attack" occurred yesterday morning, intermittently keeping Web surfers shut out from Microsoft Internet properties such as Microsoft.com and MSN.com, the company said in a statement.
The company said all sites were accessible by around noon (1700 GMT) Thursday.
The attack comes a day after the software maker fixed a server glitch that had caused additional problems with its Web sites. Microsoft said the two outages were not related.
A denial-of-service attack targets network equipment that directs Internet traffic. It occurs when hackers, using automation software, overwhelm a site with so much fake traffic that legitimate Internet users cannot get through. It's like hundreds of pranksters trying to call a single phone number at once.
Hackers do not have to break in to a site to launch such an attack, although in many cases they break into third-party computer systems and launch attacks from there to avoid tracing.
A Microsoft employee who spoke on condition of anonymity said Thursday's attack was first spotted by company technicians who were monitoring network activity.
Denial-of-service attacks are common and techniques have been developed to mitigate most of them, said Amit Yoran, chief executive of security company Riptech Inc.
Not all experts agreed. "A well-run DOS attack is really hard to defend against," said Ryan Russell, incident analyst with SecurityFocus.com, which hosts the popular security mailing list Bugtraq. "In most cases it boils down to someone with bigger pipes than you filling your pipes. There's nothing you can do except you can try to track them down."
Last February, Yahoo, Amazon.com, CNN, eBay and other major Internet sites were crippled for hours at a time by similar attacks.
