Upload the file to VirusTotal to check it against multiple antivirus engines .

Is WinRAR safe? Everything you need to know - ExpressVPN

If you open the archive to view its contents, look for hidden extensions like .exe , .scr , or .bat disguised as documents.

There is a specific Rar ransomware variant that encrypts your system's files and appends a .Rar extension to them. Safe Handling Procedures