186.rar ›

Run strings 186.rar | grep -i "flag" to see if the flag is visible in plaintext.

Open it with a hex editor; RAR4 starts with 52 61 72 21 1A 07 00 , while RAR5 starts with 52 61 72 21 1A 07 01 00 . 186.rar

If the file won't open, the magic bytes or block headers might be intentionally damaged. Run strings 186