7 Install Amavisd-new, SpamAssassin And ClamAV

To install amavisd-new, spamassassin and clamav, run the following command:

apt-get install amavisd-new spamassassin clamav clamav-daemon zoo unzip unarj bzip2

You will be asked a few questions:

Virus database update method: <– daemon
Local database mirror site: <– db.de.clamav.net (Germany; select the mirror that is closest to you)
HTTP proxy information (leave blank for none): <– (blank)
Should clamd be notified after updates? <– Yes

Now we have to edit /etc/amavis/amavisd.conf. This is a very long file with lots of comments. I have stripped out the unnecessary parts, this is with what I ended up (make sure you adjust line 112 (@lookup_sql_dsn = ( [‘DBI:mysql:database=mail;host=127.0.0.1;port=3306’, ‘mail_admin’, ‘mail_admin_password’] ); to your own database settings):

use strict;

$MYHOME = '/var/lib/amavis';   # (default is '/var/amavis')

$mydomain = 'localhost';

# $myhostname = 'host.example.com';  # fqdn of this host, default by uname(3)

$daemon_user  = 'amavis';        # (no default (undef))
$daemon_group = 'amavis';        # (no default (undef))

$TEMPBASE = $MYHOME;           # (must be set if other config vars use is)

$pid_file  = "/var/run/amavis/amavisd.pid";  # (default: "$MYHOME/amavisd.pid")
$lock_file = "/var/run/amavis/amavisd.lock"; # (default: "$MYHOME/amavisd.lock")

$ENV{TMPDIR} = $TEMPBASE;       # wise to set TMPDIR, but not obligatory

$max_servers  =  4;   # number of pre-forked children          (default 2)
$max_requests = 10;   # retire a child after that many accepts (default 10)

$child_timeout=5*60;  # abort child if it does not complete each task in n sec
                      # (default: 8*60 seconds)

# @bypass_virus_checks_acl = qw( . );  # uncomment to DISABLE anti-virus code
# @bypass_spam_checks_acl  = qw( . );  # uncomment to DISABLE anti-spam code

@local_domains_acl = ( ".$mydomain" );  # $mydomain and its subdomains

$relayhost_is_client = 0;         # (defaults to false)

$insert_received_line = 1;

$unix_socketname = undef;

$inet_socket_port = 10024;
$inet_socket_bind = '127.0.0.1';
@inet_acl = qw( 127.0.0.1 );

$DO_SYSLOG = 1;
$LOGFILE = "/var/log/amavis.log";  # (defaults to empty, no log)

#$log_level = 2;                # (defaults to 0)

$log_templ = '[? %#V |[? %#F |[?%#D|Not-Delivered|Passed]|BANNED name/type (%F)]|INFECTED (%V)], #
[?%o|(?)|<%o>] -> [<%R>|,][? %i ||, quarantine %i], Message-ID: %m, Hits: %c';

read_l10n_templates('en_US', '/etc/amavis');

$final_virus_destiny      = D_REJECT; # (defaults to D_BOUNCE)
$final_banned_destiny     = D_REJECT;  # (defaults to D_BOUNCE)
$final_spam_destiny       = D_PASS;  # (defaults to D_REJECT)
$final_bad_header_destiny = D_PASS;  # (defaults to D_PASS), D_BOUNCE suggested

$viruses_that_fake_sender_re = new_RE(
  qr'nimda|hybris|klez|bugbear|yaha|braid|sobig|fizzer|palyh|peido|holar'i,
  qr'tanatos|lentin|bridex|mimail|trojan\.dropper|dumaru|parite|spaces'i,
  qr'dloader|galil|gibe|swen|netwatch|bics|sbrowse|sober|rox|val(hal)?la'i,
  qr'frethem|sircam|be?agle|tanx|mydoom|novarg|shimg|netsky|somefool|moodown'i,
  qr'@mm|@MM',    # mass mailing viruses as labeled by f-prot and uvscan
  qr'Worm'i,      # worms as labeled by ClamAV, Kaspersky, etc
  [qr'^(EICAR|Joke\.|Junk\.)'i         => 0],
  [qr'^(WM97|OF97|W95/CIH-|JS/Fort)'i  => 0],
  [qr/.*/ => 1],  # true by default  (remove or comment-out if undesired)
);

$virus_admin = "postmaster\@$mydomain";                # due to D_DISCARD default

$mailfrom_to_quarantine = '';   # override sender address with null return path

$QUARANTINEDIR = '/var/lib/amavis/virusmails';

$virus_quarantine_to  = 'virus-quarantine';    # traditional local quarantine
$spam_quarantine_to = 'spam-quarantine';

$X_HEADER_TAG = 'X-Virus-Scanned';        # (default: undef)
$X_HEADER_LINE = "by $myversion (Debian) at $mydomain";

$undecipherable_subject_tag = '***UNCHECKED*** ';  # undef disables it

$remove_existing_x_scanned_headers = 0; # leave existing X-Virus-Scanned alone
#$remove_existing_x_scanned_headers= 1; # remove existing headers
                                        # (defaults to false)
#$remove_existing_spam_headers = 0;     # leave existing X-Spam* headers alone
$remove_existing_spam_headers  = 1;     # remove existing spam headers if
                                        # spam scanning is enabled (default)

$keep_decoded_original_re = new_RE(
# qr'^MAIL$',   # retain full original message for virus checking (can be slow)
  qr'^MAIL-UNDECIPHERABLE$',  # retain full mail if it contains undecipherables
  qr'^(ASCII(?! cpio)|text|uuencoded|xxencoded|binhex)'i,
# qr'^Zip archive data',
);

$banned_filename_re = new_RE(
#  qr'^UNDECIPHERABLE$',  # is or contains any undecipherable components
   qr'\.[^.]*\.(exe|vbs|pif|scr|bat|cmd|com|dll)$'i, # some double extensions
   qr'[{}]',     # curly braces in names (serve as Class ID extensions - CLSID)
#  qr'.\.(exe|vbs|pif|scr|bat|cmd|com)$'i,           # banned extension - basic
#  qr'.\.(ade|adp|bas|bat|chm|cmd|com|cpl|crt|exe|hlp|hta|inf|ins|isp|js|
#         jse|lnk|mdb|mde|msc|msi|msp|mst|pcd|pif|reg|scr|sct|shs|shb|vb|
#         vbe|vbs|wsc|wsf|wsh)$'ix,                  # banned extension - long
#  qr'.\.(mim|b64|bhx|hqx|xxe|uu|uue)$'i, # banned extension - WinZip vulnerab.
#  qr'^\.(zip|lha|tnef|cab)$'i,                      # banned file(1) types
#  qr'^\.exe$'i,                                     # banned file(1) types
#  qr'^application/x-msdownload$'i,                  # banned MIME types
#  qr'^application/x-msdos-program$'i,
   qr'^message/partial$'i,  # rfc2046. this one is deadly for Outcrook
#  qr'^message/external-body$'i, # block rfc2046
);

@lookup_sql_dsn =
   ( ['DBI:mysql:database=mail;host=127.0.0.1;port=3306', 'mail_admin', 'mail_admin_password'] );

$sql_select_policy = 'SELECT "Y" as local FROM domains WHERE CONCAT("@",domain) IN (%k)';

$sql_select_white_black_list = undef;  # undef disables SQL white/blacklisting

$recipient_delimiter = '+';                # (default is '+')

$replace_existing_extension = 1;        # (default is false)

$localpart_is_case_sensitive = 0;        # (default is false)

$blacklist_sender_re = new_RE(
    qr'^(bulkmail|offers|cheapbenefits|earnmoney|foryou|greatcasino)@'i,
    qr'^(investments|lose_weight_today|market\.alert|money2you|MyGreenCard)@'i,
    qr'^(new\.tld\.registry|opt-out|opt-in|optin|saveonl|smoking2002k)@'i,
    qr'^(specialoffer|specialoffers|stockalert|stopsnoring|wantsome)@'i,
    qr'^(workathome|yesitsfree|your_friend|greatoffers)@'i,
    qr'^(inkjetplanet|marketopt|MakeMoney)\d*@'i,
);

map { $whitelist_sender{lc($_)}=1 } (qw(
  nobody@cert.org
  owner-alert@iss.net
  slashdot@slashdot.org
  bugtraq@securityfocus.com
  NTBUGTRAQ@LISTSERV.NTBUGTRAQ.COM
  security-alerts@linuxsecurity.com
  amavis-user-admin@lists.sourceforge.net
  razor-users-admin@lists.sourceforge.net
  notification-return@lists.sophos.com
  mailman-announce-admin@python.org
  zope-announce-admin@zope.org
  owner-postfix-users@postfix.org
  owner-postfix-announce@postfix.org
  owner-sendmail-announce@lists.sendmail.org
  sendmail-announce-request@lists.sendmail.org
  ca+envelope@sendmail.org
  owner-technews@postel.ACM.ORG
  lvs-users-admin@LinuxVirtualServer.org
  ietf-123-owner@loki.ietf.org
  cvs-commits-list-admin@gnome.org
  rt-users-admin@lists.fsck.com
  owner-announce@mnogosearch.org
  owner-hackers@ntp.org
  owner-bugs@ntp.org
  clp-request@comp.nus.edu.sg
  surveys-errors@lists.nua.ie
  emailNews@genomeweb.com
  owner-textbreakingnews@CNNIMAIL12.CNN.COM
  yahoo-dev-null@yahoo-inc.com
));

$MAXLEVELS = 14;                # (default is undef, no limit)

$MAXFILES = 1500;                # (default is undef, no limit)

$MIN_EXPANSION_QUOTA =      100*1024;  # bytes  (default undef, not enforced)
$MAX_EXPANSION_QUOTA = 300*1024*1024;  # bytes  (default undef, not enforced)
$MIN_EXPANSION_FACTOR =   5;  # times original mail size  (must be specified)
$MAX_EXPANSION_FACTOR = 500;  # times original mail size  (must be specified)

$path = '/usr/local/sbin:/usr/local/bin:/usr/sbin:/sbin:/usr/bin:/bin';

$file   = 'file';   # file(1) utility; use 3.41 or later to avoid vulnerability

$gzip   = 'gzip';
$bzip2  = 'bzip2';
$lzop   = 'lzop';
$uncompress = ['uncompress', 'gzip -d', 'zcat'];
$unfreeze   = ['unfreeze', 'freeze -d', 'melt', 'fcat'];
$arc        = ['nomarch', 'arc'];
$unarj      = ['arj', 'unarj'];  # both can extract, arj is recommended
$unrar      = ['rar', 'unrar'];  # both can extract, same options
$zoo    = 'zoo';
$lha    = 'lha';
$cpio   = 'cpio';   # comment out if cpio does not support GNU options

$sa_local_tests_only = 0;   # (default: false)
#$sa_auto_whitelist = 1;    # turn on AWL (default: false)

# Timout for SpamAssassin. This is only used if spamassassin does NOT
# override it (which it often does if sa_local_tests_only is not true)
$sa_timeout = 30;           # timeout in seconds for a call to SpamAssassin
                            # (default is 30 seconds, undef disables it)

# AWL (auto whitelisting), requires spamassassin 2.44 or better
# $sa_auto_whitelist = 1;   # defaults to undef

$sa_mail_body_size_limit = 150*1024;

$sa_tag_level_deflt  = 3.0; # add spam info headers if at, or above that level
$sa_tag2_level_deflt = 4.0; # add 'spam detected' headers at that level
$sa_kill_level_deflt = $sa_tag2_level_deflt;

$sa_dsn_cutoff_level = 10;

$sa_spam_subject_tag = '***SPAM*** ';

$first_infected_stops_scan = 1;

@av_scanners = (

### http://www.clamav.net/
['Clam Antivirus-clamd',
  \&ask_daemon, ["CONTSCAN {}\n", "/var/run/clamav/clamd.ctl"],
  qr/\bOK$/, qr/\bFOUND$/,
  qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],
# NOTE: run clamd under the same user as amavisd;  match the socket
# name (LocalSocket) in clamav.conf to the socket name in this entry
# When running chrooted one may prefer: ["CONTSCAN {}\n","$MYHOME/clamd"],

);

@av_scanners_backup = (

  ### http://www.clamav.net/
  ['Clam Antivirus - clamscan', 'clamscan',
    "--stdout --no-summary -r --tempdir=$TEMPBASE {}", [0], [1],
    qr/^.*?: (?!Infected Archive)(.*) FOUND$/ ],

);

1;  # insure a defined return

amavisd-new is the program that glues together Postfix and SpamAssassin/ClamAV. Postfix gives the mails to amavisd-new which then invokes SpamAssassin and ClamAV to scan the emails. Please have a look at the Spamassassin and ClamAV settings in /etc/amavis/amavisd.conf. Of course, you can customize that file a lot more. Feel free to do so, and have a look at the explanations in the original /etc/amavis/amavisd.conf file!

adduser clamav amavis
/etc/init.d/amavis restart
/etc/init.d/clamav-daemon restart

Now we have to configure Postfix to pipe incoming email through amavisd-new:

postconf -e ‘content_filter = amavis:[127.0.0.1]:10024’
postconf -e ‘receive_override_options = no_address_mappings’

Afterwards append the following lines to /etc/postfix/master.cf:

amavis unix - - - - 2 smtp
        -o smtp_data_done_timeout=1200
        -o smtp_send_xforward_command=yes

127.0.0.1:10025 inet n - - - - smtpd
        -o content_filter=
        -o local_recipient_maps=
        -o relay_recipient_maps=
        -o smtpd_restriction_classes=
        -o smtpd_client_restrictions=
        -o smtpd_helo_restrictions=
        -o smtpd_sender_restrictions=
        -o smtpd_recipient_restrictions=permit_mynetworks,reject
        -o mynetworks=127.0.0.0/8
        -o strict_rfc821_envelopes=yes
        -o receive_override_options=no_unknown_recipient_checks,no_header_body_checks
        -o smtpd_bind_address=127.0.0.1

and restart Postfix:

/etc/init.d/postfix restart
postfix check
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