Cybercriminals have leaked data stolen during a ransomware attack on Vestas, the global wind power giant's CEO revealed as he said the extortion attempt against it had “failed” but it was still working to mitigate the fallout from the incident.

The Danish group switched into emergency mode after the 19 November cyberattack, which forced it to shut down some of its IT systems and was later confirmed as a ransomware incident – usually characterised by criminals taking control of data then demanding money to keep it secure.