Shortly before 4 p.m. EDT, the compromised accounts began posting similar messages requesting money be sent to cryptocurrency accounts. The messages received thousands of likes before they were taken down, only to be posted again a short while later, sometimes on the same account.
“We are aware of a security incident impacting accounts on Twitter,” the company said in a tweet. “We are investigating and taking steps to fix it. We will update everyone shortly.” Representatives for Twitter didn’t immediately respond to requests for comment.
By about 6:20 p.m. EDT, Twitter began limiting posts from verified accounts with the blue check marks, which Twitter generally designates for more prominent users. “You may be unable to tweet or reset your password while we review and address this incident,” the company posted.
The apparent bitcoin scam is the latest and by far the most extensive security failure in Twitter’s history, one that raises serious questions about a social platform that has a central place in political, cultural and business communication.
Sen. Josh Hawley (R., Mo.) sent a letter to Twitter Chief Executive Jack Dorsey requesting the company’s cooperation with the Justice Department and the Federal Bureau of Investigation to secure the platform.
“I am concerned that this event may represent not merely a coordinated set of separate hacking incidents but rather a successful attack on the security of Twitter itself,” Mr. Hawley wrote.
Tesla Inc. CEO Elon Musk’s account appears to have been one of the earliest to be compromised, along with the accounts of the bitcoin and Ripple cryptocurrencies, as well as popular digital currency exchanges including Coinbase.
The attack quickly spread across the platform, hitting numerous business leaders and other prominent figures including Mr. Gates, Amazon.com Inc. CEO Jeff Bezos, Berkshire Hathaway Inc. CEO Warren Buffett, and politicians such as Messrs. Biden and Obama. Accounts of less prominent users also were hit.
The posts appear to have prompted a number of users to send money. The bitcoin address posted by Mr. Biden received over $100,000 in bitcoin, according to Blockchain.com, a cryptocurrency exchange. Other bitcoin accounts may have been involved.
“Twitter locked down the account immediately following the breach and removed the related tweet,” said a Biden campaign official. “We remain in touch with Twitter on the matter.”
Steven Zheng, a researcher at The Block, a publication specializing in cryptocurrencies, said that he observed cryptocurrency exchange Twitter accounts, including Binance, to be among the first to be compromised. After a short period, more mainstream accounts like that of Mr. Musk were used to tweet the attackers’ messages.
Twitter has faced several high-profile hacks in the past, including last August, when Mr. Dorsey’s personal account was compromised and used to send erratic and racist tweets.
In 2017, many prominent accounts were hacked and used to broadcast pro-Turkish messages.
The breach comes as Mr. Dorsey has been under increasing pressure to boost revenue by activist investors such as Elliott Management Corp. After earlier purchasing more than $1 billion in shares and seeking Mr. Dorsey’s ouster, Elliott and the executive struck a truce that kept him in place. Twitter agreed to appoint new board members and make $2 billion in share repurchases.
Twitter has also experienced technical issues on its platform before. A glitch with its advertising software last year roiled the social-media company. The software problems meant that Twitter couldn’t serve ads to users with the same level of precision as it normally does, prompting some advertisers to pause or reduce spending.