Hawley, who has been one of the tech industry's fiercest critics on Capitol Hill, said Twitter should work with the FBI and the Justice Department after hackers took over the accounts of celebrities, Democratic politicians and billionaires, including former President Barack Obama, businessman Bill Gates, rapper Kanye West and former Vice President Joe Biden, as well as accounts of tech companies like Apple and Uber.
"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," Hawley wrote to CEO Jack Dorsey.
"As you know, millions of your users rely on your service not just to tweet publicly but also to communicate privately through your direct message service," he wrote. "A successful attack on your system's servers represents a threat to all of your users' privacy and data security."
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Suspected Bitcoin scammers had control of many of the accounts for over two hours during the late afternoon and duped at least a few hundred people into transferring the cryptocurrency.
A tweet typical of the attack said: "Everyone is asking me to give back, and now is the time. You send $1,000, I send you back $2,000."
Hawley also sent a list of questions asking Twitter about its security measures and seeking transparency about who exactly was targeted. President Donald Trump, a prolific Twitter user and critic of social media companies, has yet to weigh in, but his campaign spokesperson, Tim Murtaugh, compared the scam to Biden's tax plan in a snarky tweet.
Biden's campaign said in a statement that Twitter locked his account immediately and removed the related tweet. "We remain in touch with Twitter on the matter," the campaign said.
Twitter said in a statement that it was investigating.
"We are aware of a security incident impacting accounts on Twitter. We are investigating and taking steps to fix it. We will update everyone shortly," it said in a tweet.
The FBI's office in San Francisco, where Twitter is headquartered, also said it was aware of the scam, but it did not say whether it planned to investigate.
"The accounts appear to have been compromised in order to perpetuate cryptocurrency fraud," the office said in a statement. "We advise the public not to fall victim to this scam by sending cryptocurrency or money in relation to this incident."