# -*- Perl -*-
#***********************************************************************
#
# mimedefang-filter
#
# Suggested minimum-protection filter for Microsoft Windows clients, plus
# SpamAssassin checks if SpamAssassin is installed.
#
# Copyright (C) 2002 Roaring Penguin Software Inc.
#
# This program may be distributed under the terms of the GNU General
# Public License, Version 2, or (at your option) any later version.
#
# $Id: suggested-minimum-filter-for-windows-clients,v 1.79 2004/03/04 01:23:11 dfs Exp $
#***********************************************************************
#*********************************************************************** # Set administrator's e-mail address here. The administrator receives # quarantine messages and is listed as the contact for site-wide # MIMEDefang policy. A good example would be '[EMAIL PROTECTED]' #*********************************************************************** $AdminAddress = '[EMAIL PROTECTED]'; $AdminName = "MIMEDefang Admin";
#*********************************************************************** # Set the e-mail address from which MIMEDefang quarantine warnings and # user notifications appear to come. A good example would be # '[EMAIL PROTECTED]'. Make sure to have an alias for this # address if you want replies to it to work. #*********************************************************************** $DaemonAddress = '[EMAIL PROTECTED]';
#*********************************************************************** # If you set $AddWarningsInline to 1, then MIMEDefang tries *very* hard # to add warnings directly in the message body (text or html) rather # than adding a separate "WARNING.TXT" MIME part. If the message # has no text or html part, then a separate MIME part is still used. #*********************************************************************** $AddWarningsInline = 0;
#***********************************************************************
# To enable syslogging of virus and spam activity, add the following
# to the filter:
# md_graphdefang_log_enable();
# You may optionally provide a syslogging facility by passing an
# argument such as: md_graphdefang_log_enable('local4'); If you do this, be
# sure to setup the new syslog facility (probably in /etc/syslog.conf).
# An optional second argument causes a line of output to be produced
# for each recipient (if it is 1), or only a single summary line
# for all recipients (if it is 0.) The default is 1.
# Comment this line out to disable logging.
#***********************************************************************
md_graphdefang_log_enable('mail', 1);
#*********************************************************************** # Uncomment this to block messages with more than 50 parts. This will # *NOT* work unless you're using Roaring Penguin's patched version # of MIME tools, version MIME-tools-5.411a-RP-Patched-02 or later. # # WARNING: DO NOT SET THIS VARIABLE unless you're using at least # MIME-tools-5.411a-RP-Patched-02; otherwise, your filter will fail. #*********************************************************************** # $MaxMIMEParts = 50;
#*********************************************************************** # Set various stupid things your mail client does below. #***********************************************************************
# Set the next one if your mail client cannot handle nested multipart
# messages. DO NOT set this lightly; it will cause action_add_part to
# work rather strangely. Leave it at zero, even for MS Outlook, unless
# you have serious problems.
$Stupidity{"flatten"} = 0;# Set the next one if your mail client cannot handle multiple "inline"
# parts.
$Stupidity{"NoMultipleInlines"} = 0;# The next lines force SpamAssassin modules to be loaded and rules
# to be compiled immediately. This may improve performance on busy
# mail servers. Comment the lines out if you don't like them.
if ($Features{"SpamAssassin"}) {
spam_assassin_init()->compile_now(1) if defined(spam_assassin_init());# If you want to use auto-whitelisting:
# if (defined($SASpamTester)) {
# use Mail::SpamAssassin::DBBasedAddrList;
# my $awl = Mail::SpamAssassin::DBBasedAddrList->new();
# $SASpamTester->set_persistent_address_list_factory($awl) if defined($awl);
# }
}
# This procedure returns true for entities with bad filenames.
sub filter_bad_filename ($) {
my($entity) = @_;
my($bad_exts, $re);# Bad extensions
$bad_exts = '(ade|adp|app|asd|asf|asx|bas|chm|cmd|com|cpl|crt|dll|fxp|hlp|hta|hto|inf|ini|ins|isp|jse?|lib|lnk|mdb|mde|msc|msi|msp|mst|ocx|pcd|prg|reg|sct|sh|shb|shs|sys|url|vb|vbe|vbs|vcs|vxd|wmd|wms|wmz|wsc|wsf|wsh|\{[^\}]+\})';
# Do not allow:
# - CLSIDs {foobarbaz}
# - bad extensions (possibly with trailing dots) at end
$re = '\.' . $bad_exts . '\.*$';return 1 if (re_match($entity, $re));
# Look inside ZIP files
if (re_match($entity, '\.zip$') and
$Features{"Archive::Zip"}) {
my $bh = $entity->bodyhandle();
if (defined($bh)) {
my $path = $bh->path();
if (defined($path)) {
return re_match_in_zip_directory($path, $re);
}
}
}
return 0;
}#***********************************************************************
# %PROCEDURE: filter_begin
# %ARGUMENTS:
# None
# %RETURNS:
# Nothing
# %DESCRIPTION:
# Called just before e-mail parts are processed
#***********************************************************************
sub filter_begin () {
# ALWAYS drop messages with suspicious chars in headers
if ($SuspiciousCharsInHeaders) {
md_graphdefang_log('suspicious_chars');
# action_quarantine_entire_message("Message quarantined because of suspicious characters in headers");
# Do NOT allow message to reach recipient(s)
return action_discard();
}
# Scan for viruses if any virus-scanners are installed my($code, $category, $action) = message_contains_virus();
# Lower level of paranoia - only looks for actual viruses $FoundVirus = ($category eq "virus");
# Higher level of paranoia - takes care of "suspicious" objects # $FoundVirus = ($action eq "quarantine");
if ($FoundVirus) {
md_graphdefang_log('virus', $VirusName, $RelayAddr);
md_syslog('warning', "Discarding because of virus $VirusName");
return action_discard();
}if ($action eq "tempfail") {
action_tempfail("Problem running virus-scanner");
md_syslog('warning', "Problem running virus scanner: code=$code, category=$category, action=$action");
}
}
#***********************************************************************
# %PROCEDURE: filter
# %ARGUMENTS:
# entity -- a Mime::Entity object (see MIME-tools documentation for details)
# fname -- the suggested filename, taken from the MIME Content-Disposition:
# header. If no filename was suggested, then fname is ""
# ext -- the file extension (everything from the last period in the name
# to the end of the name, including the period.)
# type -- the MIME type, taken from the Content-Type: header.
#
# NOTE: There are two likely and one unlikely place for a filename to
# appear in a MIME message: In Content-Disposition: filename, in
# Content-Type: name, and in Content-Description. If you are paranoid,
# you will use the re_match and re_match_ext functions, which return true
# if ANY of these possibilities match. re_match checks the whole name;
# re_match_ext checks the extension. See the sample filter below for usage.
# %RETURNS:
# Nothing
# %DESCRIPTION:
# This function is called once for each part of a MIME message.
# There are many action_*() routines which can decide the fate
# of each part; see the mimedefang-filter man page.
#***********************************************************************
sub filter ($$$$) {
my($entity, $fname, $ext, $type) = @_;
return if message_rejected(); # Avoid unnecessary work
# Block message/partial parts
if (lc($type) eq "message/partial") {
md_graphdefang_log('message/partial');
action_bounce("MIME type message/partial not accepted here");
return action_discard();
}# Discard nasty attachments
if (lc($ext) eq ".bat" || lc($ext) eq ".exe" || lc($ext) eq ".pif" || lc($ext) eq ".scr") {
action_bounce("Message rejected due to unsafe attachment. Please resend without attachment.");
}
if (filter_bad_filename($entity)) {
md_graphdefang_log('bad_filename', $fname, $type);
return action_drop_with_warning("An attachment named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
}
# eml is bad if it's not multipart
if (re_match($entity, '\.eml')) {
md_graphdefang_log('non_multipart');
return action_drop_with_warning("A non-multipart attachment named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
}
# Clean up HTML if Anomy::HTMLCleaner is installed.
if ($Features{"HTMLCleaner"}) {
if ($type eq "text/html") {
return anomy_clean_html($entity);
}
}
return action_accept(); }
#***********************************************************************
# %PROCEDURE: filter_multipart
# %ARGUMENTS:
# entity -- a Mime::Entity object (see MIME-tools documentation for details)
# fname -- the suggested filename, taken from the MIME Content-Disposition:
# header. If no filename was suggested, then fname is ""
# ext -- the file extension (everything from the last period in the name
# to the end of the name, including the period.)
# type -- the MIME type, taken from the Content-Type: header.
# %RETURNS:
# Nothing
# %DESCRIPTION:
# This is called for multipart "container" parts such as message/rfc822.
# You cannot replace the body (because multipart parts have no body),
# but you should check for bad filenames.
#***********************************************************************
sub filter_multipart ($$$$) {
my($entity, $fname, $ext, $type) = @_;
return if message_rejected(); # Avoid unnecessary work
if (filter_bad_filename($entity)) {
md_graphdefang_log('bad_filename', $fname, $type);
action_notify_administrator("A MULTIPART attachment of type $type, named $fname was dropped.\n");
return action_drop_with_warning("An attachment of type $type, named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
}
# eml is bad if it's not message/rfc822
if (re_match($entity, '\.eml') and ($type ne "message/rfc822")) {
md_graphdefang_log('non_rfc822',$fname);
return action_drop_with_warning("A non-message/rfc822 attachment named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
}
# Block message/partial parts
if (lc($type) eq "message/partial") {
md_graphdefang_log('message/partial');
action_bounce("MIME type message/partial not accepted here");
return;
}return action_accept(); }
#*********************************************************************** # %PROCEDURE: defang_warning # %ARGUMENTS: # oldfname -- the old file name of an attachment # fname -- the new "defanged" name # %RETURNS: # A warning message # %DESCRIPTION: # This function customizes the warning message when an attachment # is defanged. #*********************************************************************** sub defang_warning ($$) { my($oldfname, $fname) = @_; return "An attachment named '$oldfname' was converted to '$fname'.\n" . "To recover the file, right-click on the attachment and Save As\n" . "'$oldfname'\n"; }
# If SpamAssassin found SPAM, append report. We do it as a separate
# attachment of type text/plain
sub filter_end ($) {
my($entity) = @_;# If you want quarantine reports, uncomment next line # send_quarantine_notifications();
# IMPORTANT NOTE: YOU MUST CALL send_quarantine_notifications() AFTER
# ANY PARTS HAVE BEEN QUARANTINED. SO IF YOU MODIFY THIS FILTER TO
# QUARANTINE SPAM, REWORK THE LOGIC TO CALL send_quarantine_notifications()
# AT THE END!!!
# No sense doing any extra work return if message_rejected();
# Spam checks if SpamAssassin is installed
if ($Features{"SpamAssassin"}) {
if (-s "./INPUTMSG" < 100*1024) {
# Only scan messages smaller than 100kB. Larger messages
# are extremely unlikely to be spam, and SpamAssassin is
# dreadfully slow on very large messages.
my($hits, $req, $names, $report) = spam_assassin_check();
my($score);
if ($hits < 40) {
$score = "*" x int($hits);
} else {
$score = "*" x 40;
}
# We add a header which looks like this:
# X-Spam-Score: 6.8 (******) NAME_OF_TEST,NAME_OF_TEST
# The number of asterisks in parens is the integer part
# of the spam score clamped to a maximum of 40.
# MUA filters can easily be written to trigger on a
# minimum number of asterisks...
if ($hits >= $req) {
action_change_header("X-Spam-Score", "$hits ($score) $names");
md_graphdefang_log('spam', $hits, $RelayAddr); # If you find the SA report useful, add it, I guess...
action_add_part($entity, "text/plain", "-suggest",
"$report\n",
"SpamAssassinReport.txt", "inline");
} else {
# Delete any existing X-Spam-Score header?
action_delete_header("X-Spam-Score");
}
}
} # Do Spam Header and Redirect
if (spam_assassin_is_spam()) {
# Change Subject: header
action_change_header("Subject", "*****SPAM***** $Subject");
} if (spam_assassin_is_spam()) {
# Add a header with original recipients, just for info
action_add_header("X-Orig-Rcpts", join(", ", @Recipients)); # Remove original recipients
foreach $recip (@Recipients) {
delete_recipient($recip);
} # Send to spam address
add_recipient('[EMAIL PROTECTED]');
}
# I HATE HTML MAIL! If there's a multipart/alternative with both # text/plain and text/html parts, nuke the text/html. Thanks for # wasting our disk space and bandwidth...
# If you want to strip out HTML parts if there is a corresponding # plain-text part, uncomment the next line. # remove_redundant_html_parts($entity);
md_graphdefang_log('mail_in');
# Deal with malformed MIME. # Some viruses produce malformed MIME messages that are misinterpreted # by mail clients. They also might slip under the radar of MIMEDefang. # If you are worried about this, you should canonicalize all # e-mail by uncommenting the action_rebuild() line. This will # force _all_ messages to be reconstructed as valid MIME. It will # increase the load on your server, and might break messages produced # by marginal software. Your call.
# action_rebuild(); }
# DO NOT delete the next line, or Perl will complain. 1;
Michael Sims wrote:
Jason Granat wrote:
Watching /var/log/maillog I see everytime a message comes to
[EMAIL PROTECTED] with relay 127.0.0.1 there is an error: 'reject=451 4.7.1 Please try again later' and MIMEDeFang times out. What
causes this and how do I fix it?
Can you post a link to your current mimedefang-filter?
___________________________________________
Michael Sims
Project Analyst - Information Technology
Crye-Leike Realtors
Office: (901)758-5648 Pager: (901)769-3722
___________________________________________
_______________________________________________
Visit http://www.mimedefang.org and http://www.canit.ca
MIMEDefang mailing list
[EMAIL PROTECTED]
http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
_______________________________________________ Visit http://www.mimedefang.org and http://www.canit.ca MIMEDefang mailing list [EMAIL PROTECTED] http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
