The International Committee of the Red Cross (ICRC) has revealed a major data breach that compromised the personal details of over 515,000 “highly vulnerable” victims.

It was stolen from a Swiss contractor that stores the data on behalf of the global humanitarian organization headquartered in Geneva.

The ICRC claimed it originated from at least 60 Red Cross and Red Crescent National Societies worldwide.

Some of the most vulnerable members of society are affected, including individuals separated from their families due to conflict, migration and disaster, missing persons and their families and people in detention, it added.

“An attack on the data of people who are missing makes the anguish and suffering for families even more difficult to endure. We are all appalled and perplexed that this humanitarian information would be targeted and compromised,” said Robert Mardini, the ICRC’s director-general.

“This cyber-attack puts vulnerable people, those already in need of humanitarian services, at further risk.”

There’s no indication the information has been shared publicly yet, but that’s no guarantee it won’t be in the future. That’s why Mardini pleaded with the threat actors not to leak or sell the spoils of its attack.

“Your actions could potentially cause yet more harm and pain to those who have already endured untold suffering,” he said.

“The real people, the real families behind the information you now have are among the world’s least powerful. Please do the right thing. Do not share, sell, leak or otherwise use this data.”

Given financially motivated cyber-criminals have targeted hospitals with ransomware in the past, there’s certainly no guarantee that Mardini’s words will be heard. Nor is it clear whether it was a criminal rather than a state-sponsored attack.

As a result of the attack, the ICRC said it had been forced to shut down its Restoring Family Links service, which it claims reunites 12 missing people on average with their families every day.