Migrating spamassassin to version 4.0

• Upgrade notes
• SA v. 4 docs

Install spamassassin v. 4

SA v.4 DMARC plugin requires Mail::DMARC::PurePerl, while DecodeShortURLs requires DBD::SQLite (or DBD::MariaDB or DBD::mysql), so it's better to install them before the upgrade:

perl -MCPAN -e shell
cpan> force notest install Mail::DMARC::PurePerl DBD::SQLite
cpan> quit

Stop qmail and spamd and then upgrade spamassassin, run sa-update and restart the services: 

qmailctl stop
spamdctl stop

perl -MCPAN -e shell
cpan> force notest install Mail::SpamAssassin Mail::SpamAssassin::Plugin::Razor2
cpan> quit

sa-update
spamdctl start
qmailctl start

Load the new plugins

• DMARC
• ExtractText
• DecodeShortURLs

Load all plugins commented out in /etc/mail/spamassassin/v400.pre. Then add your config to your local.cf.

ExtractText

• Thanks to Gabriel Torres for reviewing and correcting this section

The purpose of the ExtractText plugin is to, when enabled, convert attachments (including images, byt the use of an OCR) into plain text in order to SpamAssassin to apply its rules to this text. So if we receive doc/pdf/images with spammy text in them, SpamAssassin will now be able to safely mark the email as spam.

In order to do that, we need to have installed some external programs in our server. The configuration lines added to local.cf have to load these programs to scan each message attachment.

Install the required external programs. Debian users will do;

apt-get install antiword
apt-get install docx2txt
apt-get install unrtf
apt-get install odt2txt
apt-get install tesseract-ocr
apt-get install poppler-utils

Add the following lines to the local.cf file:

ifplugin Mail::SpamAssassin::Plugin::ExtractText

extracttext_external pdftotext /usr/bin/pdftotext -nopgbrk -layout -enc UTF-8 {} -
extracttext_use pdftotext .pdf application/pdf

# http://docx2txt.sourceforge.net
extracttext_external docx2txt /usr/bin/docx2txt {} -
extracttext_use docx2txt .docx application/docx

extracttext_external antiword /usr/bin/antiword -t -w 0 -m UTF-8.txt {}
extracttext_use antiword .doc application/(?:vnd\.?)?ms-?word.*

extracttext_external unrtf /usr/bin/unrtf --nopict {}
extracttext_use unrtf .doc .rtf application/rtf text/rtf

extracttext_external odt2txt /usr/bin/odt2txt --encoding=UTF-8 {}
extracttext_use odt2txt .odt .ott application/.*?opendocument.*text
extracttext_use odt2txt .sdw .stw application/(?:x-)?soffice application/(?:x-)?starwriter

extracttext_external tesseract {OMP_THREAD_LIMIT=1} /usr/bin/tesseract -c page_separator= {} -
extracttext_use tesseract .jpg .png .bmp .tif .tiff image/(?:jpeg|png|x-ms-bmp|tiff)

add_header all ExtractText-Flags _EXTRACTTEXTFLAGS_

#header PDF_NO_TEXT X-ExtractText-Flags =~ /\bNoText\b/
#describe PDF_NO_TEXT PDF without text
#score PDF_NO_TEXT 0.2

#header DOC_NO_TEXT X-ExtractText-Flags =~ /\bNoText\b/
#describe DOC_NO_TEXT Document without text
#score DOC_NO_TEXT 0.2

#header EXTRACTTEXT exists:X-ExtractText-Flags
#describe EXTRACTTEXT Email processed by extracttext plugin
#score EXTRACTTEXT 0.001

endif

You can see three rules commented out. You can safely leave them commented out or enable them for debug purposes. The EXTRACTTEXT rule is just to have proof that the plugin is active. PDF_NO_TEXT and DOC_NO_TEXT will be hit in case of an empty document in attach. You will have an header like this when these two rules have been hit:

X-Spam-ExtractText-Flags: NoText

Update the RC's sauserprefs plugin

Update your johndoh/roundcube-sauserprefs plugin by downloading it from github, as the v. 1.20.1 version is not yet available as a composer installable plugin.

cd /var/www/roundcube/htdocs/plugins
wget https://github.com/johndoh/roundcube-sauserprefs/archive/refs/tags/1.20.1.tar.gz
tar xzf 1.20.1.tar.gz
mv roundcube-sauserprefs-1.20.1/ sauserprefs
cd sauserprefs
mv config.inc.php.dist config.inc.php

Setup MySQL login. Then turn this flag to true to gain spamassassin v.4 compatibility:

$config['sauserprefs_sav4'] = true;

All rules, functions, command line options and modules that contain "whitelist" or "blacklist" have been renamed to contain more racially neutral "welcomelist" and "blocklist" terms. So we have to update our sauserprefs DB records. Use this php scriplet from command line to do the job, after adjusting your mysql login:

cat > sauserprefs_blocklist_welcomelist.php << __EOF__
#!/usr/bin/php
<?php
/************************************************************************************************
Finds and replaces deprecated strings blacklist_from/whitelist_from in spamassassin.userpref
db table to blocklist_from/welcomelist_from respectively.
************************************************************************************************/

\$host = "localhost";
\$database = "spamassassin";
\$user = "spamassassin";
\$password = "xxxxxxxxxxxxxxxxxx";

\$link = mysqli_connect(\$host, \$user, \$password, \$database) or die("Unable to connect to MySQL");
\$query ="UPDATE userpref SET preference = REPLACE(REPLACE(preference, 'whitelist_from', 'welcomelist_from'), 'blacklist_from', 'blocklist_from')";
mysqli_query(\$link, \$query) or die(mysqli_error(\$link));
print "job done\n";
__EOF__

chmod +x sauserprefs_blocklist_welcomelist.php
./sauserprefs_blocklist_welcomelist.php

mv roundcube-sauserprefs-1.20.1/ sauserprefs
mv config.inc.php.dist config.inc.php

mv roundcube-sauserprefs-1.20.1/ sauserprefs
cd sauserprefs
mv config.inc.php.dist config.inc.php

score        PDF_NO_TEXT  0.001zzz

score        PDF_NO_TEXT  0.001

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