I'll have to set up a example, so I can explain this better.
Say I have the following directory setup:
In /public_html I have the domain rootsite.com pointing to /public_html/ I have site1.com pointing to /public_html/site1/ and site2.com to /public_html/site2/.
Now the problem is there could be a injected file in /site1 that uses:
$fh = fopen('../index.php', 'w');
fwrite($fh, "You've been hacked\n");
I want to restrict this somehow from happening, without blocking web access. Anything with htaccess I can implement?