Since Friday's breach more than 200,000 victims - including the NHS in the United Kingdom - across 150 countries have been infected by the Wanna Decryptor ransomware, also known as WannaCry.
IT comes as NHS Digital said it "continues to work around the clock alongside the National Cyber Security Centre, to support NHS organisations that have reported any issues related to this cyber-attack".
What you can do to stay protected?
Security firms have spent the weekend analysing the WannaCry/WanaDecryptor ransomware code, producing a series of best-practice advice to help individuals and organisations to avoid infection.
Highlighting an incident at Papworth Hospital near Cambridge where a nurse clicked on a malicious link and malware infected her computer and started to encrypt sensitive files, he wrote in his study, "Fortunately, the hospital's daily data backup had just been completed".
The cyber attack last week, which is known as WannaCry and demands Bitcoin payment in exhange for access to locked files, has affected 48 health organisations across England and Scotland, causing 16 to shut down their IT systems.
As a ransomware program, WannaCry itself is not that special or sophisticated.
Despite the vast spread of WannaCry, it is believed that the perpetrators have only raised around $20,000 in payments so far, and have yet to actually withdraw the payments; no easy feat as many eyes will be on the transactions in order to trace the attackers.
Even if your business isn't technology-focused, it can still waste time and money responding to a cyber attack.
Cyber criminals frequently launch ransomware campaigns.
In a blog post on Sunday, Microsoft President Brad Smith appeared to tacitly acknowledge what researchers had already widely concluded: The ransomware attack leveraged a hacking tool, built by the U.S. National Security Agency, that leaked online in April.
There are fears of more cyber attacks as people begin work after the weekend, although few have been reported so far. More on that a little later.
The most important thing to remember is that however tempting it may be, you should not pay the ransom.
Back up your data on offline hard drives. Also, be cautious about any USB sticks or other hardware that has been plugged into the victim's machine.
What is Wanna Decryptor Ransomware? If not, it's likely you're on your own. CJ CGV Co. was restoring its advertising servers at dozens of its movie theatres after the attack left the company unable to display trailers of upcoming movies.
How can I protect myself against ransomware?
The ransomware, called "WannaCry", is spread by taking advantage of a Windows vulnerability that Microsoft released a security patch for in March. Because of the extremely high impact, Microsoft has made a decision to issue patches for ALL operating systems, including the unsupported ones. The same goes for all your other software.
"This is a wake-up call for the NHS but also more generally to businesses around the country". Some of the victims have reportedly regained access to their files after paying, although security experts advise against complying with ransom demands.
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