RansomWhere? 1.2.5 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free software for Mac OS X is an intellectual property of Objective-see LLC. The software lies within Security Tools, more precisely Personal Security.
From the developer:
RansomWhere? is a utility with a simple goal; generically thwart OS X ransomware. It does so by identifying a commonality of essentially all ransomware; the creation of encrypted files. Generally speaking, ransomware encrypts personal files on your computer, then demands payment (the ransom) in order for you to decrypt your files.
You may want to check out more Mac applications, such as PasswordWallet, Protect Files or RPG, which might be similar to RansomWhere?.