I'm just going to copy their horribly incorrect Listing 5: 

#!/usr/bin/perl
        use CGI;

        my $var1 = CGI->new();
        my $parameter = $cgi->param('text');

        print $var1->header();
        print "parameter";

[download]

Where is $cgi ever defined? $var1 is the cgi object. How is this script vulnerable to scripting attacks? They print out the text 'parameter', not the variable $parameter. Someone really fudged things up here.

Their methods for 'filtering' input are just weird. Anyone who just throws s/[^A-Za-z0-9 ]*/ /g; to filter input is just being... stupid? Invalid data should not be filtered out, it should be outright rejected and the user should be reprompted for valid input.

In reply to Re: Introdutory article on cross site scripting by Anonymous Monk
in thread Introdutory article on cross site scripting by greenFox

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