French researchers claim cure for WannaCry-infected computers

What Kaspersky's findings also show is the importance of keeping your operating system fully patched and up to date - Microsoft pushed out a fix for WannaCrypt to Windows 7 users back in March.

The fact that Guinet has open sourced the tool might help other researchers to come up with a solution for other Windows versions.

According to a report in the Financial Times, Microsoft failed to provide the update fixing the vulnerability for free to Windows XP users.

The data comes amid criticism over Microsoft's approach to releasing patches on older versions of its operating system.

Wannakey was able to successfully scour the memory of an infected XP machine and extract the p and q variables that the secret key was based on. "If you want to kill WannaCry, fix broken Windows". The British government cancelled a nationwide NHS support contract with Microsoft after a year, leaving upgrades to local trusts.

Since Microsoft has already confirmed that more recent versions of Windows aren't vulnerable to WannaCry, it's quite obvious that most of the infections would affect Windows 7-powered computers.

Microsoft declined to comment for this story. The spy tools in question were recently the subjects of leaks, which might explain how they've ended up in the hands of cyber criminals.

WannaCry hit many systems, but hospitals in the United Kingdom in particular suffered significant damage, causing reported closures of entire wards. Windows Server 2008 R2 accounted for a majority of the remaining 2 percent.

The last few days have seen an increase in scrutiny of security measures in the wake of the ransomware attack that has surfaced in companies across the world. Through this technique, hackers hold your computer hostage by encrypting nearly all the data on your device until you pay the ransom amount asked by the hacker.

An unknown number of computers sit behind the 300,000 infected internet connections identified by Kryptos.

"As a result of the malicious WannaCry software being spread, we recorded isolated cases of credit organisations' resources being compromised", the central bank said. The company is crunching data to arrive at a firmer estimate it aims to release later yesterday. Upon payment of the ransom, the files would be decrypted and all would be well. Companies needing to restore their operations right away likely would have turned to backups, if available, by now.

He added that the software helps recover the prime numbers of the RSA private key used by WannaCry.

One week after Wannacry started its global online rampage, security researchers now have a better understanding of how the ransomware spread so quickly, ensnaring over 300,000 computers in more than 150 countries.

Given the very specific way in which the tool works, it only functions if the infected computer has not been rebooted since the WannaCry ransomware and the associated memory has not been allocated and erased by another process.