And that would be ... me?
The following, I posted at the OP's previous Topic "Migrating to Linux...", specifically, here -
Retrace your steps into Cinnamon's File Manager, known as Nemo (you can find that if you click Help-About). Down to File System and over to the Var folder, as you have done previously.
Now at Var, or at its next level down, where folder Log resides, stop for a moment. Right-click Var or Log and choose "open as root", and enter your password. If you do this at Var, you don't need to do it again at Log. You only need to do it at one level above the information you wish to see or data and files/folders you wish to manipulate.
You will have a new Window opened, likely including a red strip about elevated privileges. Proceed to where rkhunter.log is and you will find it no longer has a cross over it.
Double-click and the file will open. You can either wade through it all (may be 1,700 lines or more, as it is with me, rather daunting?) or fast-track to the warnings.
Ctrl-end will take you to the last line of the file, and clicking that line will tell you how many lines in your status bar.
A few lines above that is likely to be where your warnings are. In my case I had 5-6 lines.
If you can't see the warnings that easily, then Ctrl-Home to the start of the file, press Ctrl-F for Find, and enter "warning" and go from there.
The applet you are in while you are reading is called gedit (in Cinnamon and in Ubuntu Unity and some others). It is an unformatted text editor such as Notepad is in Windows.
When you are finished and exit, and close down the elevated privileges window of Nemo, the root privileges will be restored on what you have left.
I can illustrate that with screenshots if asked, put them in a spoiler, whatever.
For the references to Cinnamon and its File Manager (FM) Nemo, the user can substitute his own FM under his own Distro.
Different Distros use different protocols as to whether they provide the facility to right-click and open as Administrator/Root, and some, not at all. If you are in that situation, then simply start your FM as Root and proceed from there. This can be done from Terminal, typing in eg
... where Thunar is your File Manager. You are prompted for your password, enter it and away you go.
The above is valid for Debian-based Distros - RPM and other families may differ slightly in syntax.