In the wake of the attack, Microsoft released a patch for computers running older operating systems, including Windows IX, Windows 8 and Windows Server 2003. 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.
May 15, 2017 by Chloe Best Protect your computer and devices from the cyber attack that has hit 150 countries around the world with this advice from the National Cyber Security Centre.
The malicious "ransomware" attacks that seized computers worldwide Friday and held those systems hostage are likely to worsen this week as millions of people return to work - forcing them to discover the hard way whether they have been affected, security analysts said.
"This just highlights the importance of patching up immediately", said Bei-Tseng "Bill" Chu, who teaches in UNC Charlotte's Department of Software and Information Systems.
Derriford was one of a number of NHS hospitals across the country hit by malware called Wanna Decryptor.
Internet security professionals fear new versions of the worm dubbed "WannaCry". Network security companies Fortinet and Proofpoint could also move. The virus took control of users' files and demanded $300 payments via Bitcoin to restore access.
Security experts say pirated software is particularly vulnerable to security threats, but so far no evidence has emerged indicating whether that played any role in the virus's spread in China. The exploit was leaked last month as part of a trove of USA spy tools.
"We're in the face of an escalating threat, the numbers are going up. We don't know when the problem can be solved", said the spokesman, who spoke on condition of anonymity.
The blame game has already started.
"Repeatedly, exploits in the hands of governments have leaked into the public domain and caused widespread damage", Smith wrote.
"An equivalent scenario with conventional weapons would be the U.S. military having some of its Tomahawk missiles stolen".
"At this stage it's likely that at least one business has been impacted". That was "unheard of six months ago", Levy said.
The most disruptive attacks were reported in the United Kingdom, where hospitals and clinics were forced to turn away patients after losing access to computers.
'Of course there are amounts that are being demanded, in this case relatively small amounts - $US300 rising to $US600 if you don't pay within three days, ' he said.
"As a result, cybercriminals will continue their activity and look for new ways to exploit systems that result in more infections and more money in their accounts", Europol said in a statement.
Japanese media reported that 2,000 computers at 600 companies and organisations in the country had been affected, citing the Japan Computer Emergency Response Team Coordination Center. The company said the virus has been localized and "technical work is underway to destroy it and update the antivirus protection".
NHS computer systems are expected to "return to normal" today, the Scottish Government has said.
Microsoft said the situation was "painful" and that it was taking "all possible actions to protect our customers".
In England, 48 NHS trusts fell victim, as did 13 NHS bodies in Scotland. There was no data loss or impact on other services.
Anti-virus experts Symantec said the majority of organisations affected were in Europe.