The developers of Locky Ransomware have decided to change the extension of encrypted files. This time, the developers moved away from Norse gods and into Egyptian mythology by using the.osiris extension for encrypted files. There is still no way to decrypt Locky encrypted files for free. This campaign is being distributed through Excel email attachments that contain macros to download and install Locky. The names of the ransom notes have changed for the OSIRIS Locky variant and are now named DesktopOSIRIS.
Source: https://www.bleepingcomputer.com/news/security/locky-ransomware-switches-to-egyptian-mythology-with-the-osiris-extension/