Ryuk has plagued the public and private sectors alike over the past years, generating hundreds of millions of ransom revenues for the criminals behind it. Usually deployed via an existing malware infection within a targets network, Ryuk wreaks havoc on any system that can be accessed, encrypting data using a combination of RSA and AES. One of the latest versions of Ryuk, changes were made to the way the length of the footer is calculated. As a result, the decryptor will truncate files, cutting off one too many bytes in the process of decrypting the file.”]
Source: https://blog.emsisoft.com/en/35023/bug-in-latest-ryuk-decryptor-may-cause-data-loss/