modsec on shared server

[hd-sam]

Hi,

I'm running 4.1.12. I've noticed modsec is working on most accounts on our shared server, but not on some of them. It's very odd...

I'm throwing this out there, but I noticed it works on all WordPress sites that have a working .htaccess file.

It doesn't seem to be working on standard html sites. However it does work properly when I switch to apache

My method for testing this is by running:
http://domain.com/foo.php?foo=http://www.example.com

If the above gives 404 modsec is not working
If it gives a 403 then it is working, and I have verified this by watching the error_log which displays the activated modsec rule

Any ideas?

[UPDATE]
I have actually verified this.
I added an empty index.php file to an account that was not working. (this account has basic html files).
I also added an .htaccess file containing the basic wordpress .htaccess file of :

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

After I've done that and test modsec again it creates a 403 error and appears to be working..
As soon as I remove the .htaccess file or index.php file, it stops working and displays a 404 instead.

Again, this is tested by looking to see if a 404 or 403 error appears on this URL: http://domain.com/foo.php?foo=http://www.example.com