Hackers reportedly stole the personal data of more than 200 million Twitter users and shared these details on a hacking website, including email addresses and phone numbers.
The incident "will, unfortunately, lead to a lot of hacking, targeted phishing and doxxing," said Alan Gal, co-founder of Israeli cybersecurity monitoring firm Hudson Rock, on Wednesday.
Describing the breach as "one of the most significant leaks" he has seen in his entire life, Gal first posted it on the business-focused social networking site LinkedIn on Dec. 24.
Screenshots of the hacker forum, where the data appeared Wednesday, have circulated online.
Twitter has not responded to any posts mentioning the breach nor commented on the report shared by the security researcher.
It is not clear if the social media platform has taken any steps yet to investigate or deal with the issue.
The identity of those behind the hack is still unknown, along with other details.
It may have happened as early as 2021, well before millionaire Elon Musk took over the company last October in a $44 billion deal that has been followed by controversy and turmoil.
Claims about the size and scope of the breach initially varied with early accounts last December, saying that 400 million e-mail addresses and phone numbers were stolen.
