'Tough day' for Jack Dorsey, massive Twitter hack: Things you should know

1 / 7

Twitter accounts of a series of high-profile figures and companies were hijacked on Wednesday, to promote an apparent Bitcoin scam. The hacker shared a series of tweets through different accounts asking followers that if they transferred cryptocurrency to a specific bitcoin wallet, they would receive double the money in return.

2 / 7

These tweets were repeatedly deleted and re-posted by some of the compromised accounts over the course of Wednesday afternoon. So far, the crypto address mentioned in the tweets received more than $110,000 Bitcoins.

3 / 7

Twitter accounts of Amazon founder Jeff Bezos, investor Warren Buffett, Microsoft co-founder Bill Gates, US presidential candidate Joe Biden, reality television show star Kim Kardashian, former US President Barack Obama, billionaire Elon Musk, rapper Kanye West, and Michael Bloomberg were seemingly hacked to solicit digital currency.

4 / 7

Twitter said employees with access to its internal systems had been successfully targeted by hackers who “used this access to take control of many highly-visible (including verified) accounts and Tweet on their behalf.”

5 / 7

Chief Executive Jack Dorsey earlier said the company was diagnosing the problem and pledged to share “everything we can when we have a more complete understanding of exactly what happened.” “Tough day for us at Twitter. We all feel terrible this happened,” he said in a tweet.

6 / 7

While account compromises are not rare, experts were surprised at the sheer scale and coordination of the incident and raised questions about Twitter's cybersecurity. "This appears to be the worst hack of a major social media platform yet," said Dmitri Alperovitch, who co-founded cybersecurity company CrowdStrike. "It is highly likely that the attackers were able to hack into the back end or service layer of the Twitter application," said Michael Borohovski, director of software engineering at security company Synopsys.

7 / 7

Twitter users with verified accounts started to be able to send tweets again, after the company had silenced some of its highest-profile users in response to an hours-long security incident. Twitter had limited some users' ability to tweet, reset passwords and use other unspecified "account functions" after many of the platform's top accounts were hacked and used to solicit digital currency.