HTTP authentication can be used to password protect web pages
The Apache web server implements HTTP authentication. This can be configured via a .htaccess file
There is a security risk from tainted data --- data entered by a user which is used for subsequent system interaction
Perl has built-in checking for tainted data, which can be turned on my using the -T command line switch
Data can be untainted by referencing a substring in a match, as shown in perldoc perlsec.
Some web servers use cgiwrap to run CGI scripts under their owner's user ID.
Secure HTTP can be used to provide an encrypted channel of communication between the web client and server.