Twitter CEO Jack Dorsey says he doesn't currently have a phone number after his account was hacked to send out racist tweets

REUTERS/Toby Melville

Twitter CEO Jack Dorsey.

• Twitter CEO Jack Dorsey has broken five days of Twitter silence following the hijacking of his account on Friday, when hackers took over his account and tweeted racial slurs including the n-word. Twitter eventually locked the hackers out of the account and deleted the offensive tweets.
  
• Jack's first public post after the hijacking was "Hello Melbourne", an innocuous reference to his world tour. But he gave a nod to the hack in an exchange with New York Times journalist Kate Conger, and ended speculation that he had been at Burning Man during the hack.
  
• Dorsey told Conger that he doesn't currently have a phone number following the hack, a SIM swap attack that gave the hackers access to his phone number.
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Twitter CEO Jack Dorsey is tweeting again five days after a hacker group called the "Chuckling Squad" gained access to his account and used it to tweet racist slurs.

"Hello Melbourne," Dorsey tweeted early Wednesday morning, apparently continuing his months-long world tour.

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Dorsey didn't initially make any reference to Friday's hack, but then alluded to it in a tweet exchange with New York Times journalist Kate Conger.

The exchange started with a jokey tweet from Conger: "is @jack back from the playa yet?"

"Playa" is a reference to the Burning Man festival in Nevada, an event that has garnered huge popularity among Silicon Valley tech workers and executives. Some people joked that Dorsey was away at Burning Man when his account was being hacked.

Dorsey replied to say he'd only been to Burning Man once, in 2005, adding "why do you ask?" 

"Because I haven't seen you on The Website," said Conger, referring to Twitter and Dorsey's silence over his hack.

"Had an issue with my carrier..." the Twitter CEO responded.

Dorsey's account was hacked using a technique called SIM swapping, in which hackers gain access to the phone number associated with an account through the victim's phone service provider. They then used Twitter's "tweet-to-text" service to send a number of offensive tweets, including repeated use of the n-word and references to the Chuckling Squad.

It's likely that Dorsey's number was suspended as part of the attempts to regain control of his Twitter account.

Replying to another tweet from Conger, Dorsey explained that he hasn't got a replacement phone number yet.