NEW YORK (CNNMoney) -- One of the Web's largest blog hosting sites, Wordpress, struggled to keep functioning Thursday through a massive distributed denial of service (DDoS) attack.
Matt Mullenweg, Wordpress' founding developer, called the assault "the largest and most sustained attack we've seen in our six year history." Its effects hit all three data centers run by Automattic, the San Francisco developer that owns Wordpress.
"It's currently been neutralized, but it's possible it could flare up again later," Mullenweg said Thursday afternoon. "We suspect it may have been politically motivated against one of our non-English blogs, but we're still investigating and have no definitive evidence yet."
Wordpress hosts 18 million sites and does a weekly average of around 600 million pageviews. Its blogging platform powers parts of CNNMoney.
The company notified its paying subscribers of the attack Thursday morning.
"We are working to mitigate the attack, but because of the extreme size, it is proving rather difficult," it wrote in an e-mail alert. "The size of the attack is multiple Gigabits per second and tens of millions of packets per second."
But by the afternoon, the effects had subsided, and Wordpress' status site reported that operations were running normally.
DDoS attacks are unsophisticated but extremely hard for websites to defend against. The attacker directs a giant traffic surge to its target, overwhelming the site's servers and making it hard for legitimate users to access the site.
Mastercard.com and Visa.com struggled last year under similar attacks. In contrast, some of the Web's largest sites -- like Google and Amazon.com -- are frequent targets but have the resources to scale up as needed to fend off most denial-of-service attempts.
Efforts to unionize low-wage employees of fast-food franchisees and outside contractors get lift from decision of NLRB. More
The U.S. economy has performed well this year. But there's lots of global gloom. Which will influence the Fed the most? More
The market volatility in China and the U.S. could hit private companies, especially late-stage unicorns. More
Looking for something good on Netflix? These entertaining films will help you learn more about finance and investing. More