THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
loadplugin Mail::SpamAssassin::Plugin::iXhash /path/to/iXhash.pm
# This makes DNS queries time out after 10 seconds (2x default)
ixhash_timeout 10
# This list uses iX Magazine's spam as datasource.
body IXHASH eval:ixhashtest('ix.dnsbl.manitu.net')
describe IXHASH This mail has been classified as spam @ iX Magazine, Germany
tflags IXHASH net
score IXHASH 1.5
# This list comes in @ spamtraps run by LogIn & Solutions AG, Germany
# Manually verified stuff
body LOGINHASH1 eval:ixhashtest('nospam.login-solutions.de')
describe LOGINHASH1 mail has been classified as spam @ LogIn&Solutions AG, Germany
tflags LOGINHASH1 net
score LOGINHASH1 1.5
# This list contains hashes from Mails classified as spam at a larger company based in Germany
# Lots of stuff, but automatically categorized and contributed
body LOGINHASH2 eval:ixhashtest('nospam.login-solutions.ag')
describe LOGINHASH2 mail has been classified as spam @ unknown company, Germany
tflags LOGINHASH2 net
score LOGINHASH2 1.5
=head1 NAME
Mail::SpamAssassin::Plugin::iXhash - compute fuzzy checksums from mail bodies and compare to known spam ones via DNS
=head1 SYNOPSIS
loadplugin Mail::SpamAssassin::Plugin::iXhash /path/to/iXhash.pm
ixhash_timeout 10
body IXHASH eval:ixhashtest('ix.dnsbl.manitu.net')
describe IXHASH This mail has been classified as spam @ iX Magazine, Germany
tflags IXHASH net
score IXHASH 1.5
=head1 DESCRIPTION
iXhash.pm is a plugin for SpamAssassin 3.0.0 and up. It takes the body of a mail, strips parts from it and then computes a hash value from the rest.
These values will then be looked up via DNS.
This plugin is based on parts of the procmail-based project 'NiX Spam', developed by Bert Ungerer.(un@ix.de)
For more information see http://www.heise.de/ix/nixspam/. The procmail code producing the hashes only can be found here:
ftp://ftp.ix.de/pub/ix/ix_listings/2004/05/checksums
Parts of the code were submitted via heise forum by 'kungfuhasi'
See http://www.heise.de/ix/foren/go.shtml?read=1&msg_id=7246759&forum_id=48292.
Martin Blapp (mb@imp.ch) found and solved a problem occuring on Perl 5.8.7. Thanks a lot!
Further improvements (DNS timeouts) by Dallas Engelken (dallase@uribl.com) - see comments for details.
=cut
package Mail::SpamAssassin::Plugin::iXhash;
use strict;
use Mail::SpamAssassin;
use Mail::SpamAssassin::Plugin;
use Mail::SpamAssassin::Util;
use Digest::MD5 qw(md5 md5_hex md5_base64);
use Net::DNS;
use Net::DNS::Resolver;
# Locale - this was on Bert's wishlist
use POSIX qw(locale_h);
setlocale(LC_CTYPE, "de_DE.ISO8859-1");
# LC_CTYPE now "Deutsch, Deutschland, codeset ISO 8859-1"
# Maybe not appropriate for spam that is neither German nor English
use vars qw(@ISA);
@ISA = qw(Mail::SpamAssassin::Plugin);
sub dbg { Mail::SpamAssassin::dbg (@_); }
sub new {
my ($class, $mailsa, $server) = @_;
$class = ref($class) || $class;
my $self = $class->SUPER::new($mailsa);
bless ($self, $class);
$self->set_config($mailsa->{conf});
$self->register_eval_rule ("ixhashtest");
return $self;
}
sub set_config {
my ($self, $conf) = @_;
my @cmds = ();
# implements ixhash_timeout config option - by dallase@uribl.com
push(@cmds, {
setting => 'ixhash_timeout',
default => 5,
type => $Mail::SpamAssassin::Conf::CONF_TYPE_NUMERIC,
});
$conf->{parser}->register_commands(\@cmds);
}
sub ixhashtest {
my ($self, $permsgstatus,$muell,$dnsserver) = @_;
dbg("IXHASH: IxHash querying Server $dnsserver");
my ($digest,$answer,$ixdigest,$body) = "";
my @body = $permsgstatus->{msg}->get_body();
my $resolver = Net::DNS::Resolver->new;
my $body_copy = "";
foreach (@body) {
$body .= join "", @$_;
}
my $rr;
my $hits = 0;
# alarm the dns query - dallase@uribl.com
# --------------------------------------------------------------------------
# here we implement proper alarms, ala Pyzor, Razor2 plugins.
# keep the alarm as $oldalarm, so we dont loose the timeout-child alarm
# see http://issues.apache.org/SpamAssassin/show_bug.cgi?id=3828#c123
my $oldalarm = 0;
my $timeout = $permsgstatus->{main}->{conf}->{'ixhash_timeout'} || 5;
eval {
Mail::SpamAssassin::Util::trap_sigalrm_fully(sub { die "ixhash timeout reached"; });
$oldalarm = alarm($timeout);
#-----------------------------------------------------------------------
# Creation of hash # 1 if following conditions are met:
# - mail contains at least 16 spaces or tabs
# - mail consists of at least 2 lines
if (($body =~ /([\s\t].+?){16,}/ ) && ($body =~ /.*$.*/)){
# All space class chars just one time
# Do this in two steps to avoid Perl segfaults
# if there are more than 2.600 identical chars to be replaced
# Step One
$body_copy =~ s/([[:space:]]{100})(?:\1+)/$1/g;
# Step Two
$body_copy =~ s/([[:space:]])(?:\1+)/$1/g;
# remove graph class chars and some specials
$body_copy =~ s/[[:graph:]]+//go;
# Create actual digest
$digest = md5_hex($body_copy);
dbg ("IXHASH: Computed hash-value $digest via method 1");
dbg ("IXHASH: Now checking $digest.$dnsserver");
# Now check via DNS query
$answer = $resolver->search($digest.'.'.$dnsserver, "A", "IN");
if ($answer) {
foreach $rr ($answer->answer) {
next unless $rr->type eq "A";
dbg ("IXHASH: Received reply from $dnsserver:". $rr->address);
$hits = 1 if $rr->address;
}
}
}
# End of computing hash #1
#---------------------------------------------------------------------
#---------------------------------------------------------------------
# Creation of hash # 1 if mail contains at least 3 of the following characters:
# '[<>()|@*'!?,]' or the combination of ':/'
# (To match something like "Already seen? http:/host.domain.tld/")
if ($body =~ /((([<>\(\)\|@\*'!?,])|(:\/)).*?){3,}/m ) {
$body_copy = $body;
# remove redundant stuff
$body_copy =~ s/[[:cntrl:][:alnum:]%&#;=]+//g;
# replace '_' with '.'
$body_copy =~ tr/_/./;
# replace duplicate chars. This too suffers from a bug in perl
# so we do it in two steps
# Step One
$body_copy =~ s/([[:print:]]{100})(?:\1+)/$1/g;
# Step Two
$body_copy =~ s/([[:print:]])(?:\1+)/$1/g;
# Computing hash...
$digest = md5_hex($body_copy);
dbg ("IXHASH: Computed hash-value $digest via method 2");
dbg ("IXHASH: Now checking $digest.$dnsserver");
# Now check via DNS query
$answer = $resolver->search($digest.'.'.$dnsserver, "A", "IN");
if ($answer) {
foreach $rr ($answer->answer) {
next unless $rr->type eq "A";
dbg ("IXHASH: Received reply from $dnsserver:". $rr->address);
$hits = 1 if $rr->address;
}
}
}
# End of computing hash #2
#-----------------------------------------------------------------------
#-----------------------------------------------------------------------
# Compute hash # 3 if
# - there are at least 8 non-empty characters in the body
# - neither hash #1 nor hash #2 have been computed
if (($body =~ /[\S]{8,}/) and (length($digest) < 32)) {
$body_copy = $body;
$body_copy =~ s/[[:cntrl:][:space:]=]+//g;
# replace duplicate chars. This too suffers from a bug in perl
# so we do it in two steps
# Step One
$body_copy =~ s/([[:print:]]{100})(?:\1+)/$1/g;
# Step Two
$body_copy =~ s/([[:graph:]])(?:\1+)/$1/g;
# Computing actual hash
$digest = md5_hex($body_copy);
dbg ("IXHASH: Computed hash-value $digest via method 3");
dbg ("IXHASH: Now checking $digest.$dnsserver");
# Check via DNS
$answer = $resolver->search($digest.'.'.$dnsserver, "A", "IN");
if ($answer) {
foreach $rr ($answer->answer) {
next unless $rr->type eq "A";
dbg ("IXHASH: Received reply from $dnsserver:". $rr->address);
$hits = 1 if $rr->address;
}
}
}
if (defined $oldalarm) {
alarm $oldalarm; $oldalarm = undef;
}
}; # End of sub ixhashtest
# Error handling - parto of Dallas' code
if ($@ =~ m/timeout/) {
dbg("IXHASH: $timeout second timeout exceeded while checking $digest.$dnsserver");
}
return $hits;
}
1;