Microsoft released a security patch for the vulnerabilities in March. The exploit was leaked last month as part of a trove of US spy tools. They just happen to hit the motherlode. Cyber security experts say the brunt of the attacks were felt in Russian, including the country's largest mobile phone company.
In China, "hundreds of thousands" of computers at almost 30,000 institutions could have been hit, according to a report by Qihoo 360, an internet security firm.
Microsoft warned governments on Sunday against storing computer vulnerabilities like the leaked one at the heart of the cyberattack that has crippled computers in more than 150 countries.
In the meantime, the Reserve Bank of India (RBI) has issued an advisory asking all banks to put in place a software update at ATMs to prevent their systems from a malware that has attacked payment systems across the world.
Security experts said his move bought precious time for organizations seeking to block the attacks.
The CERT-In has suggested some anti-ransomware measures: Check regularly for the integrity of the information stored in the databases, do not open attachments in unsolicited emails even if they come from people in your contact list and never click on a URL contained in an unsolicited email, even if the link seems benign.
This certainly is a "wake up call" for governments.
"Our general advice would be first and foremost that systems have been patched, and the most up to date security controls", Meah said. "Previous concerns of a wide-scale infection of domestic institutions did not eventuate".
Kyodo News said one personal computer was affected at one office at East Japan Railway Co., but train services were not affected. Once it infects one computer within a network, it can spread to all the computers in that network "within seconds", said Israel Levy, the CEO of the cybersecurity firm Bufferzone.
He said ransomware attacks are an everyday occurrence, and that victims tend to be small businesses that don't have as much money to invest in cybersecurity.
In India, authorities were on high alert for news of malfunctioning computers after Kapersky Lab's warning.
"There are other criminals who've launched this attack, and they are ultimately responsible for this", he said from his home in Oxford, England.
To stymie "WannaCrypt" attacks - which encrypted files on thousands of PCs used by the U.K.'s National Health Service (NHS), causing chaos in many hospitals - Microsoft published patches for Windows XP, Windows 8 and Windows Server 2003. According to The Guardian, the United Kingdom attacks hit at least 16 National Health System (NHS) facilities and directly compromised the information technology (IT) systems that are used to ensure patient safety.
In France, auto manufacturer Renault said one of its plants, which employs 3,500 people in Douai, northern France, wasn't reopening Monday as technicians continued to deal with the aftermath of the global cyberattack.
Security officials in Britain urged organizations to protect themselves by installing the security fixes, running antivirus software and backing up data elsewhere. He added that the malware was an "extremely serious threat" that could inspire copycat attacks.
Run Windows Update: Updating your computer should ensure you have the latest security software to protect against viruses or malware. This one worked because of a "perfect storm" of conditions, including a known and highly unsafe security hole in Microsoft Windows, tardy users who didn't apply Microsoft's March software fix, and malware created to spread quickly once inside university, business and government networks.
The government is not legally bound to notify at-risk companies.