Switzerland's Reporting and Analysis Centre for Information Assurance (MELANI), confirmed that seven companies were known to have been affected in the attacks and said it was analyzing the malware.
For security reasons, it did not name the affected companies, but multimedia publisher Admeira said on Tuesday that it had been affected by the attacks. Its website was still down on Wednesday.
“We are working urgently to analyze the situation and take action,” Admeira said on Tuesday afternoon.
The global cyber attack started spreading on Tuesday in Ukraine, which was the most severely hit country with the metro network, government departments and the central bank all affected.
Worldwide, the ransomware has affected companies including Russian oil company Rosneft, a major Dutch shipping firm, and British advertising agency WPP.
Affected Windows computers are frozen, with a message appearing on screens promising to recover files in return for a $300 ransom to be paid in the digital Bitcoin currency.
Experts are unsure about the origins and purpose of the attack, and by Wednesday afternoon said they had found a 'vaccine' which could stop a machine being affected, but not a so-called kill switch.
This week's attack comes just more than a month after the WannaCry Ransomware attack, which affected 200 Swiss IP addresses and more than 300,000 computers worldwide.
No major organizations in Switzerland were affected by that attack, though it brought Britain's National Health Service, Spain's national telecom provider Telefonica and US delivery service FedEx to a standstill.
According to MELANI, the latest attack exploits the same vulnerability known from the WannaCry attack, but also uses other methods which make it “much harder to protect against”.