Suspicious Appended Extension for Ransomware
Detects file renames where the target filename uses an uncommon double extension. This behavior is often associated with ransomware activity, where files are encrypted and then renamed with a custom extension, such as ".jpg.crypted" or ".docx.locky". The rule specifically looks for common document and image file extensions followed by another extension, while filtering out known legitimate backup or temporary file extensions.
Sigma
