The shares of Talktalk Telecom Group PLC (LON:TALK) plummeted due to cyber attack on its website, which could lead to a potential lawsuit from consumers claiming that the company violated data protection laws.

The stock price of Talktalk Telecom declined more than 12% to 225.30 pence per share in London.

Talktalk Telecom

Hackers failed to access Talktalk’s core systems

Talktalk Telecom said the cyber criminals gained access to its website, but not its core systems. The company added that the extent of financial information, which may have been stolen by hackers were “materially lower” than initially thought.

TalkTalk Telecom provides fixed line broadband, voice telephony, mobile, and television services to approximately four million customers in the United Kingdom. According to the company, it does not store complete credit card details (a series of numbers were concealed) on its website.

TalkTalk Telecom said the hackers would not be able to use the incomplete credit card details for a financial transaction.The hacker also failed to access account passwords.

Criminal investigation is ongoing

On Friday, Taltalk Telecom’s spokesperson disclose that a person claiming to be responsible for hacking contacted the company are demanded a ransom for the stolen financial information.

The Metropolitan Police Cyber Crime Unit is conducting a criminal investigation of the cyber attack in Talktalk’s website. The company is working with leading cyber crime specialist and the Metropolitan Police to determine what happened and the extent of information accessed.

“Right from the start, we’ve done everything we can to get to the bottom of what happened as soon as possible and to keep you updated along the way,” according to the company in a statement.

Talk talk e-mailed every customer directly regarding the incident. The company will also send letters to those who does not have emails. The company added that it is working to restore most of its services and to bring My Account back online.

A separate report from the Sunday Times suggested that the Information Commissioner’s Office, which enforces the Data Protection Act, may also launch an investigation into the hacking incident. The agency could impose a £500,000 fine against Talktalk if found to have breached any regulation.

Talktalk CEO Dido Harding emphasized that the company followed all of its legal obligations regarding storing financial information.