A foreign power compromised the cybersecurity of the state-owned Irish power grid company EirGrid, Ireland's Independent newspaper reports.
The report, issued Monday in Ireland, says that the telecommunications company Vodafone discovered last month that hackers had compromised its systems more than two months prior.
The attackers then installed eavesdropping software on the routers used by EirGrid and were able to see encrypted communications sent by the company.
According to the Independent, sources at the National Cyber Security Centre in Ireland and Vodafone believe that the attack was "state sponsored." The intent of the attack was not clear, and it is not clear whether malware was installed on EirGrid's internal systems.
Though a series of cyberattacks in Ukraine have caused power outages, power plants far more commonly face hacking with the purpose of espionage.
EirGrid transports wholesale electricity around Ireland.
The Independent reports that the internet addresses used in the attack came from Bulgaria and Ghana, but that typically means hackers routed the attack through hacked systems in those countries and were not necessarily from Bulgaria and Ghana.