The attack was announced on Saturday evening and the group claiming to be behind the intrusion claims to have obtained 280 gigabytes of data.
Svenska kraftnät confirms that the agency has been subjected to a data breach.
"We are now trying to find out what information has been leaked and how it can affect us. We see no indications that the power system is affected", says Cem Göcgören, information security manager at Svenska kraftnät, in the press release.
State-owned Svenska kraftnät is the responsible authority for the operation of the grid and also responsible for ensuring that the power system works in a crisis, war or during other serious disruptions.
The attack has been reported to the police and the Swedish Civil Contingencies Agency (MSB) is involved.
The hacker group Everest has announced via its site on the darknet that they intend to publish the data stolen from Svenska kraftnät on Saturday evening if the agency does not follow their instructions. It is unclear what kind of data it is.
The group has previously attacked and tried to blackmail a large number of companies and authorities in several parts of the world. They have, among other things, specialized in stealing databases, including customer and employee registers.
Cert-se, the part of MSB that is to handle and prevent IT incidents, is following the development and supporting Svenska kraftnät with expertise "based on the needs that arise", according to MSB's press service.
The government is also following the development of the event.
"We are in close contact with the agency", says Minister for Energy and Business Ebba Busch in a statement on X.
