Wordpress has been attacked by a botnet of "tens of thousands" of individual computers since last week, according to server hosters Cloudflare and Hostgator.
The botnet targets Wordpress users with the username "admin", trying thousands of possible passwords.
The attack began a week after Wordpress beefed up its security with an optional two-step authentication log-in option.
The site currently powers 64m websites read by 371m people each month.
According to survey website W3Techs, around 17% of the world's websites are powered by Wordpress.
Read more: http://www.bbc.co.uk/news/technology-22152296
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