Even ransomware operators make mistakes, and in the case of ransomware gang the Key Group, a cryptographic error allowed a team of security researchers to develop and release a decryption tool to restore scrambled files. The decryptor only works on a specific version of the ransomware built around August 3, according to threat intel provider ElectricIQ, which spotted the criminals’ mistakes and exploited them to develop the Python-based restoration tool.  It’s available for free:

Source: The Register