Files with osiris file extension may be since December 2016 encountered as renamed and encrypted files affected by the Locky ransomware.
OSIRIS file extension - Locky (variant) ransomware affected data
What is osiris file? How to open osiris files?
File type specification:
File extension osiris was in December 2016 used as a new suffix for the Locky ransomware that previously used locky, odin and thor extensions for example.
Much like previous variants of Locky, also this version is distributed through WS, JS, etc email attachments attached to emails (spams).
Should the user execute the scripts from the attachment, an encrypted DLL installer will be downloaded and launched through Windows' Rundl32.exe.