The data breach took place last Sunday, on November 19. The stolen data comprise of the laboratory’s employees’ critical data, which was later leaked on online forums. 

The investigation on the breach is being carried out by the U.S. Cybersecurity and Infrastructure Security Agency (CISA) and the FBI, who are working in collaboration with INL, a spokesperson informed. Physical addresses, bank account details, and Social Security numbers are among the data that are impacted.

In an interview regarding the incident, the spokesperson told local news outlet EastIdahoNews.com that the breach has impacted INL’s Oracle HCM system, a cloud-based workforce management platform that offers payroll and other HR solutions, was impacted by the attack.

SiegedSec, a self-entitled hacktivist group has since taken responsibility of the attack, following which it published a sample of the stolen employee data online, which included full names, dates of birth, email addresses, contact details and other identity info of the INL employees to their data breach forum. 

The group, which seems to have political motivations, was also accused in the past of stealing information from the Communities of Interest Cooperation Portal, an unclassified information-sharing portal run by NATO.

However, INL has not implied that the breach has had any impact on its classified information or nuclear research, and CISA did not immediately respond to the request for a comment. 

Regardless of whether the classified nuclear details were accessed by the threat actors, Colin Little, security engineer at the cybersecurity firm Centripetal, said it is "highly disconcerting that the staff generating that intellectual property and participating in the most advanced nuclear energy research and development have had their information leaked online."

"Now those who are politically motivated and would very much like to know the names and addresses of the top nuclear energy researchers in the U.S. have that data," he said. 

INL supports large-scale initiatives from the Department of Energy, the Department of Defense. The laboratory bills itself as "a world leader in securing critical infrastructure systems and improving the resiliency of vital national security and defense assets."