WannaCry Decription Tool WanaKiwi Works on Windows XP, 2003, Vista, 2008 and 7

Now that WannaCry infections have dropped somewhat, saviors come to our help, bringing decryption keys. So far, two have been confirmed to work. One is WannaKey, that we've already reported on, and another is WanaKiwi. 

Developed by researcher Benjamin Delpy, also known as gentilkiwi, WanaKiwi works on multiple Windows versions. Europol also confirmed the decryption tool is effective. 

There's a catch before running WanaKiwi, however - you have to keep your machine running after the infection. That means no reboot is allowed. This is because prime numbers may be overwritten in the system's memory after a while, which would lower the chances of the tool being effective. 

WanaKiwi works on both Windows XP and Windows 7. "This would imply it work...