"Israeli cyber-intelligence firm Hudson Rock appeared to be the first to notice the posting offering the data of 400 million Twitter users, tweeting about the “credible threat” three days ago."

When threat actors are able to extract sensitive information due to neglectful API implementations, the consequence is equivalent to a data breach and should be handled accordingly by the firm [and] examined by regulators,” Gal told TechCrunch.

"A database of that size containing the private information such as phone numbers of a lot of Facebook's users would certainly lead to bad actors taking advantage of the data to perform social-engineering attacks [or] hacking attempts," Gal told Insider.

“In the case of the T-Mobile attack, the alleged hacker said they had different motivations. In a screenshot of a text conversation posted online by Alon Gal, co-founder of cybercrime firm Hudson Rock, the hacker appears to tell Gal that the attack was done “to harm US infrastructure.”