Microsoft estimates over 12,000 machines have been hit by the cyberattack. According to security firm McAfee, the malware has spread across the U.S., large parts of Europe, South America, and big countries in Asia too.
Major corporations have also been affected including WPP, Maersk, Russian oil giant Rosneft, and public and private institutions in Ukraine. Some of those businesses responded on Wednesday.
WPP said that it has taken steps to contain the attack with the priority now to return to normal operations. Many of the businesses under the WPP brand were affected but they are "experiencing no or minimal disruption."
Maersk said that IT systems were down across multiple sites and some business units, but the issues have been contained. It is now working on a "technical recovery plan". The impact on the business is still being assessed.
Russia, which was one of the countries hit, said the cyberattack caused no serious problems at either a state or corporate level in the country.