On Twitter, users questioned whether anyone could feel secure on the site after the high-profile compromise, while others shuddered at what the consequences would be if President Donald Trump's account were hijacked.
This suggests that the hackers were able to hijack or spoof the phone number linked to Dorsey's Twitter account, and then simply tweet via SMS.
Hackers have taken over Jack Dorsey's Twitter account, and tweeted and retweeted offensive and racist content.
The hacker posted a series of offensive messages from Dorsey's including racial slurs and re-tweeted a message supporting Nazi Germany.
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It's not the first time Dorsey has temporarily lost control of his account.
The tweets have since been deleted, and Twitter has released a statement about the incident. "Encouraging any kind of hacking is in direct violation of our Terms of Service". "We are aware of this incident and both the server and the server owner were permanently removed from Discord within minutes of this being reported to us". "We're working on it and investigating what happened".
An additional tweet also claimed that if people did not follow one specific account, then the Twitter HQ was 'blowing up'.
Twitter declined to comment when asked if Mr Dorsey used a two-factor login for his account.