NAME

Apache::AntiSpam::SpamTrap - Add SpamTrap suffix to local-part in Email

SYNOPSIS

# in httpd.conf
<Location /antispam>
SetHandler perl-script
PerlAddVar Key 0123456789ABCDEF
PerlHandler Apache::AntiSpam::SpamTrap
</Location>

# filter aware
PerlModule Apache::Filter
SetHandler perl-script
PerlSetVar Filter On
PerlHandler Apache::RegistryFilter Apache::AntiSpam::SpamTrap Apache::Compress

DESCRIPTION

Apache::AntiSpam::SpamTrap is a subclass of Apache::AntiSpam, filter module to prevent e-mail addresses exposed as is on web pages. This module adds a Blowfish encrypted string suffix to the local-part of e-mail addresses. This string contains a timestamp and the IP address of the remote host. This enables you to identify a spammer's address harvester by its IP address and take steps to prosecute him.

The encryption prevents faking and may help in a prosecuting attemp.

For example, apleiner@cpan.org will be filtered to apleiner-78c1ed6da0322b3a@cpan.org.

This module is Filter aware, meaning that it can work within Apache::Filter framework without modification.

You need to give the Blowfish key in your Apache configuration file.

To decode a received mail's SpamTrap string use the following function:

sub spamtrap_decode
  {
    my ($string, $key) = @_;
    return unless $key;
    return unless $string =~ /[0-9a-f]{16}/o;
    my $inkey = pack("H16", $key);
    use Crypt::Blowfish;
    my $cipher = new Crypt::Blowfish $inkey;
    my $plaintext = $cipher->decrypt(pack("H*", $string));
    my $time = unpack("L", substr($plaintext, 4, 4));
    my $ip = join(".", map { ord } split //, substr($plaintext, 0, 4));
    return wantarray ? ($ip, $time) : "$ip $time";
  }

TODO

• should make local address part be configured.

AUTHOR

Alex Pleiner <alex@zeitform.de> - zeitform Internet Dienste 2003

This work is based on the Apache::AntiSpam::* modules provided by Tatsuhiko Miyagawa <miyagawa@bulknews.net>. The idea is taken from Daniel A. Rehbein (http://daniel.rehbein.net/).

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

SEE ALSO

Apache::AntiSpam