Photo/Illutration A notice by Pandora on a site on the dark web indicates that it conducted a cyberattack against Denso Corp. (Tatsuya Sudo)

A hacker group has claimed responsibility for the theft of sensitive corporate information from a major parts supplier to Toyota Motor Corp. group and is threatening to soon release the information online.

Officials at Denso Corp. confirmed that the company had suffered a ransomware attack on its business hub in Germany last week.

A group of cybercriminals that calls itself Pandora posted a statement online on March 13 claiming responsibility for the attack.

The statement was published on the dark web, which is hidden from public view and requires the use of specific software to be accessed.

Pandora is threatening to publicly disclose internal company information on March 16. It claims to have 1.4 terabytes of data, consisting of more than 157,000 pieces of information, including purchase orders and technical drawings.

Denso said the company is in the middle of its investigation into what kind of information was stolen.

Denso declined to confirm whether the culprit is demanding a ransom, but it has reported the incident to German law enforcement authorities.

The company became aware of the cyberattack on March 10 when employees detected computer system glitches, officials said.

Denso’s hub in Germany oversees sales, design and development of automotive parts.

The company said it is not aware of any damage to its sales order-management processes, which are carried out at a separate office. Sales activities have not been disrupted by the attack, it added.

This latest cyberattack followed one against its operations in Mexico in December. Hackers gained unauthorized access to its computer system and obtained personal information about Denso employees.

Kojima Press Industry Co., also a parts supplier in Aichi Prefecture, suffered a system failure from a cyberattack late February, forcing all Toyota factories in Japan to be shut down on March 1.

(This article was written by Kohei Kondo and senior staff writer Tatsuya Sudo.)