TL;DR: WinRar installation has a bug revealed, only the beta installation will have the fix: the screenshot represent the screenshot of the current official page to download winrar. WinRar stable installation has dropped the use of insecure UNACEV2.DLL in the newest beta installation, the documentation about the bug is described in full detail here: https://research.checkpoint.com/extracting-code-execution-from-winrar/ The more easy to digest version is explained here: https://www.theregister.co.uk/2019/02/20/winrar_security_bug/ Since the site and the users have heavy usage of compressed files, every one is a potential target if they are not aware of the details. I would recommend the site to auto check if any compressed file is indeed a .ACE renamed file, because it could take advantage of the situation to target users when they open manually.