A group of hackers has compromised Amazon's cloud services and used them to mine bitcoins.

According to the report of the security intelligence group RedLock, at least two companies were compromised, which are the British insurance group Aviva and Netherland-based international digital security company Gemalto. Both companies, as well as Amazon, did not respond to requests for comment, Business Insider reports.

Cybercriminals did not steal any confidential data, that is why they were not detected by the security systems. Hackers were interested only in getting access to computer power for bitcoin mining.

“Upon deeper analysis, the team discovered that hackers were executing a bitcoin mining command from one of the Kubernetes containers,” reads the RedLock report.

Earlier, Kaspersky Lab reported that in 2017 at least 1.65 million computers are mining cryptocurrencies for hackers.