To secure the web content from the hacker by executing the .pl or .cgi script, we can refer to the following code under the .htaccess file, so that when ever hacker try to execute the .pl or .cgi script, the script will show the plain text content instead of scripts execution result.
Create the simple .htaccess file or use the existing .htaccess file present under the root of your domain and insert the following code.
AddType text/plain .pl .cgi
or
Addhandler text/plain .pl .cgi