HTML-Scrubber-StripScripts

NAME

HTML::Scrubber::StripScripts - strip scripting from HTML

SYNOPSIS

use HTML::Scrubber::StripScripts;

       my $hss = HTML::Scrubber::StripScripts->new(
          Allow_src      => 1,
          Allow_href     => 1,
          Allowamailto => 1,
          Whole_document => 1,
          Block_tags     => ['hr'],
       );

       my $clean_html = $hss->scrub($dirty_html);

DESCRIPTION

This module provides a preworked configuration for HTML::Scrubber, configuring it to leave as much non-scripting markup in place as possible while being certain to eliminate all scripting constructs. This allows web applications to display HTML originating from an untrusted source without introducing XSS (cross site scripting) vulnerabilities.

CONSTRUCTORS

new ( CONFIG )

        Returns a new "HTML::Scrubber" object, configured with a filtering
        policy based on a whitelist of XSS-free tags and attributes. If
        present, the CONFIG parameter must be a hashref. The following keys
        are recognized (unrecognized keys will be silently ignored).

        "Allow_src"
            By default, the scrubber won't be configured to allow constructs
            that cause the browser to fetch things automatically, such as
            "SRC" attributes in "IMG" tags. If this option is present and
            true then those constructs will be allowed.

        "Allow_href"
            By default, the scrubber won't be configured to allow constructs
            that cause the browser to fetch things if the user clicks on
            something, such as the "HREF" attribute in "A" tags. Set this
            option to a true value to allow this type of construct.

        "Allowamailto"
            By default, the scrubber won't be configured to allow "MAILTO:"
            URLs in "HREF" attributes in "A" tags. Set this option to a true
            value to allow them. Ignored unless "Allow_href" is true.

        "Whole_document"
            By default, the scrubber will be configured to deal with a
            snippet of HTML to be placed inside another document after
            scrubbing, and won't allow "head" and "body" tags and so on.

            Set this option to a true value if an entire HTML document is
            being scrubbed.

        "Block_tags"
            If present, this must be an array ref holding a list of lower
            case tag names. These tags will be removed from the allowed
            list.

            For example, a guestbook CGI that uses "HR" tags to separate
            posts might wish to disallow the "HR" tag in posts, even though
            "HR" presents no XSS hazard.

BUGS

All scripting is safely removed, but no attempt is made to ensure that there is a matching end tag for each start tag. That could be a problem if the scrubbed HTML is to be inserted into a larger HTML document, since "FONT" tags and so on could be maliciously left open.
If that's a big problem for you, consider using the more heavyweight (and probably much slower) HTML::StripScripts module instead.

SEE ALSO

HTML::Scrubber, HTML::StripScripts

AUTHOR

Nick Cleaton <nick@cleaton.net>

COPYRIGHT

        This module is free software; you can redistribute it and/or modify
        it under the same terms as Perl itself.