You can redirect 403 (Forbidden) request to 404 (Not Found)
403 (Forbidden Request) give a clue that you got a correct path and you don’t have permission to access. This confirms file/folder exist and it’s restricted.
Thus, 403 (Forbidden Request) allow the hacker to know more about your file system structure and room for security vulnerabilities.
There are many ways to achieve this, below example using mod_rewrite
1. Enable mod_rewrite.so module in your httpd.conf of Apache/IBM HTTP Server
LoadModule rewrite_module modules/mod_rewrite.so
2. Turn on RewriteEngine and write RewriteRule
RewriteEngine On RewriteRule ^/test/?$ /404 [L] RewriteRule ^/test?$ /404 [L]
Note: the test is your Alias/Directory which request will be forwarded to 404 (Not Found) request.
3. Restart Apache/IBM HTTP Server
Let me know how it goes.