A security researcher developed a tool called wanadecrypt to restore encrypted files from Windows XP PCs infected by the WannaCry ransomware. The tool allows retrieving the secret encryption keys used by the malware for free, it works on Windows XP, Windows 7, Windows Vista, Windows Server 2003 and 2008 operating systems. Experts downplayed the discovery because Windows XP computers werent affected by the massive Wannacry attack. The WannaKey tool is not available to anyone who has been infected by Wanna Cry.”]
Source: https://securityaffairs.co/wordpress/59234/malware/wanadecrypt-wannacry.html