TalkTalk

Hackers targeted UK telco TalkTalk in February 2017, which stole information, including credit card data, on 157,000 customers.

They sent a ransom message to TalkTalk demanding 465 bitcoins (worth $125,550 at the time.

TalkTalk sent the data breach letters to all affected customers and asked them to be alerted.

Source: https://www.vice.com/en/article/pgxa3m/convicted-talktalk-blackmailer-warns-young-hackers-about-falling-into-crime

"id": "TAL232161122",
"linkid": "talktalk",
"type": "Breach",
"date": "02/2017",
"severity": "100",
"impact": "5",
"explanation": "Attack threatening the organization’s existence"