Inhaltsverzeichnis

Header und Bodychecks mit Postfix 2.11.3 unter CentOS 7.x

Bild: Symbolbild Postfix und SPAM Bei der Überlegungen zu den Anforderungen an unseren Mailserver haben wird uns schon mal grundsätzlich Überlegt, das Thema Header- und Bodychecks bei der Bewertung von Nachrichten mit einzubeziehen.

Ob die Filterung von From:-Headern ein geeignetes Mittel beim der SPAM-Bewertung sein kann, muss sich jeder selbst gut überlegen, ist es doch ein leichtes Absenderangaben beim From:-Headern zu fälschen. Nichts desto Trotz, kommt es immer wieder vor, dass Kunden Nachrichten, die einem bestimmten Muster folgen, nicht mehr haben wollen. Wir werden bei der Konfiguration unseres Mailservers also soweit vorbereiten, dass im Notfall schnell und einfach entsprechende Regeln bei den Header- wie auch Body-Checks angelegt und genutzt werden können.

main.cf

Damit wir später die einfache Möglichkeiten haben, basierend auf bestimmte Inhalte im Mailheader bzw. Mailbody, Nachrichten zu bewerten oder gar zu manipulieren, werden wir nun noch unsere Postfix-Hauptkonfigurationsdatei main.cf erweitern.

Wir legen uns in unserer Konfigurationsdatei /etc/postfix/main.cf eine neue Section SPAM ABWEHRMECHANISMEN - INTERNER POSTFIX CONTENT-FILTER an. Dort verweisen wir auf die beiden Lookup-Tebellen zur Contentfilterung.

 # vim /etc/postfix/main.cf
...
 
################################################################################
## SPAM ABWEHRMECHANISMEN - INTERNER POSTFIX CONTENT-FILTER
#
# Django : 2014-10-15 - Lookup-Tabelle zum Verwalten der Routinen zur
#          inhaltliche Prüfung der eMail-Header. Nach dem Ändern der Tabelle
#          header_check_maps ist ein "systemctl reload postfix.service"
#          durchzuführen, damit Postfix diese neu einliest!
# default: header_checks =
header_checks = pcre:/etc/postfix/header_checks_map
 
# Django : 2014-10-15 - Lookup-Tabelle zum Verwalten der Routinen zur
#          inhaltliche Prüfung der eMail-Bodies. Nach dem Ändern der Tabelle
#          body_check_maps ist ein "systemctl reload postfix.service"
#          durchzuführen, damit Postfix diese neu einliest!
# default: body_checks =
body_checks = pcre:/etc/postfix/body_checks_map

Voraussetzung hierzu (Perl Compatible Regular Expressions) ist natürlich die Unterstützung des installierten Postfix. Mit folgender Abfrage können wir überprüfen, ob pcre unterstützt wird.

 # postconf -m | grep pcre
 pcre

Die pcre-Unterstützung bei Postfix 2.11.3 unter CentOS 7.x ist natürlich bereits vorhanden!

Trifft das gewählte Suchmuster bei unseren PRCE1) zu, so haben wir unter anderem folgene Möglichkeiten:

Im Konfigurationsverzeichnis von Postfix finden wir für weitere Beschreibungen die Manpage für den Einsatz und die Verwendung der body- und header-checks. Dort finden sich jede Menge hilfreicher Tips zur Postfix built-in Content Inspection von Wietse Venema.

 # less /etc/postfix/main.cf
/etc/postfix/main.cf
# HEADER_CHECKS(5)                                              HEADER_CHECKS(5)
# 
# NAME
#        header_checks - Postfix built-in content inspection
# 
# SYNOPSIS
#        header_checks = pcre:/etc/postfix/header_checks
#        mime_header_checks = pcre:/etc/postfix/mime_header_checks
#        nested_header_checks = pcre:/etc/postfix/nested_header_checks
#        body_checks = pcre:/etc/postfix/body_checks
# 
#        postmap -q "string" pcre:/etc/postfix/filename
#        postmap -q - pcre:/etc/postfix/filename <inputfile
# 
# DESCRIPTION
#        This  document  describes access control on the content of
#        message headers and message body lines; it is  implemented
#        by  the  Postfix  cleanup(8) server before mail is queued.
#        See access(5) for access control  on  remote  SMTP  client
#        information.
# 
#        Each  message  header  or  message  body  line is compared
#        against a list of patterns.  When a  match  is  found  the
#        corresponding action is executed, and the matching process
#        is repeated for the next message header  or  message  body
#        line.
# 
#        For  examples, see the EXAMPLES section at the end of this
#        manual page.
# 
#        Postfix header or body_checks are designed to stop a flood
#        of  mail from worms or viruses; they do not decode attach-
#        ments, and they do not unzip archives. See  the  documents
#        referenced  below  in the README FILES section if you need
#        more sophisticated content analysis.
# 
#        Postfix supports four built-in content inspection classes:
# 
#        header_checks
#               These   are  applied  to  initial  message  headers
#               (except for the headers  that  are  processed  with
#               mime_header_checks).
# 
#        mime_header_checks (default: $header_checks)
#               These  are  applied to MIME related message headers
#               only.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        nested_header_checks (default: $header_checks)
#               These  are  applied  to message headers of attached
#               email messages (except for  the  headers  that  are
#               processed with mime_header_checks).
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        body_checks
#               These are applied to all other  content,  including
#               multi-part message boundaries.
# 
#               With Postfix versions before 2.0, all content after
#               the initial message headers is treated as body con-
#               tent.
# 
#        Note: message headers are examined one logical header at a
#        time, even when a message  header  spans  multiple  lines.
#        Body lines are always examined one line at a time.
# 
# COMPATIBILITY
#        With Postfix version 2.2 and earlier specify "postmap -fq"
#        to query a table that contains case sensitive patterns. By
#        default,  regexp: and pcre: patterns are case insensitive.
# 
# TABLE FORMAT
#        This document assumes that header  and  body_checks  rules
#        are  specified  in  the form of Postfix regular expression
#        lookup tables. Usually the best  performance  is  obtained
#        with pcre (Perl Compatible Regular Expression) tables, but
#        the slower regexp (POSIX regular expressions)  support  is
#        more  widely  available.  Use the command "postconf -m" to
#        find out what lookup table types your Postfix system  sup-
#        ports.
# 
#        The general format of Postfix regular expression tables is
#        given below.  For a  discussion  of  specific  pattern  or
#        flags   syntax,   see  pcre_table(5)  or  regexp_table(5),
#        respectively.
# 
#        /pattern/flags action
#               When /pattern/ matches the  input  string,  execute
#               the  corresponding  action. See below for a list of
#               possible actions.
# 
#        !/pattern/flags action
#               When /pattern/ does not  match  the  input  string,
#               execute the corresponding action.
# 
#        if /pattern/flags
# 
#        endif  Match the input string against the patterns between
#               if and endif, if and only if the same input  string
#               also matches /pattern/. The if..endif can nest.
# 
#               Note:  do not prepend whitespace to patterns inside
#               if..endif.
# 
#        if !/pattern/flags
# 
#        endif  Match the input string against the patterns between
#               if  and endif, if and only if the same input string
#               does not match /pattern/. The if..endif can nest.
# 
#        blank lines and comments
#               Empty lines and whitespace-only lines are  ignored,
#               as  are  lines whose first non-whitespace character
#               is a `#'.
# 
#        multi-line text
#               A pattern/action line  starts  with  non-whitespace
#               text.  A line that starts with whitespace continues
#               a logical line.
# 
# TABLE SEARCH ORDER
#        For each line of message input, the patterns  are  applied
#        in  the order as specified in the table. When a pattern is
#        found that  matches  the  input  line,  the  corresponding
#        action  is  executed  and  then  the  next  input  line is
#        inspected.
# 
# TEXT SUBSTITUTION
#        Substitution of substrings  from  the  matched  expression
#        into  the action string is possible using the conventional
#        Perl syntax ($1, $2, etc.).   The  macros  in  the  result
#        string  may  need  to  be  written as ${n} or $(n) if they
#        aren't followed by whitespace.
# 
#        Note: since negated patterns (those preceded by !)  return
#        a result when the expression does not match, substitutions
#        are not available for negated patterns.
# 
# ACTIONS
#        Action names are case insensitive. They are shown in upper
#        case for consistency with other Postfix documentation.
# 
#        DISCARD optional text...
#               Claim  successful delivery and silently discard the
#               message.  Log the optional text if specified,  oth-
#               erwise log a generic message.
# 
#               Note:   this  action  disables  further  header  or
#               body_checks inspection of the current  message  and
#               affects all recipients.  To discard only one recip-
#               ient without discarding the entire message, use the
#               transport(5) table to direct mail to the discard(8)
#               service.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        DUNNO  Pretend  that the input line did not match any pat-
#               tern, and inspect the next input line. This  action
#               can be used to shorten the table search.
# 
#               For  backwards  compatibility reasons, Postfix also
#               accepts OK but it is (and always has been)  treated
#               as DUNNO.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#        FILTER transport:destination
#               Write a content filter request to the  queue  file,
#               and  inspect  the  next input line.  After the com-
#               plete message is received it will be  sent  through
#               the specified external content filter.  More infor-
#               mation about external content  filters  is  in  the
#               Postfix FILTER_README file.
# 
#               Note: this action overrides the content_filter set-
#               ting, and affects all recipients of the message. In
#               the  case  that  multiple FILTER actions fire, only
#               the last one is executed.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        HOLD optional text...
#               Arrange  for  the  message to be placed on the hold
#               queue, and inspect the next input line.   The  mes-
#               sage  remains  on hold until someone either deletes
#               it or releases it for delivery.  Log  the  optional
#               text if specified, otherwise log a generic message.
# 
#               Mail that is placed on hold can  be  examined  with
#               the  postcat(1)  command,  and  can be destroyed or
#               released with the postsuper(1) command.
# 
#               Note: use "postsuper -r" to release mail  that  was
#               kept  on  hold for a significant fraction of $maxi-
#               mal_queue_lifetime  or  $bounce_queue_lifetime,  or
#               longer.  Use "postsuper -H" only for mail that will
#               not expire within a few delivery attempts.
# 
#               Note: this action affects  all  recipients  of  the
#               message.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        IGNORE Delete the current line from the input, and inspect
#               the next input line.
# 
#        PREPEND text...
#               Prepend  one  line  with  the  specified  text, and
#               inspect the next input line.
# 
#               Notes:
# 
#               o      The prepended text is output on  a  separate
#                      line,  immediately  before  the  input  that
#                      triggered the PREPEND action.
# 
#               o      The prepended text is not considered part of
#                      the  input  stream:  it  is  not  subject to
#                      header/body checks or address rewriting, and
#                      it does not affect the way that Postfix adds
#                      missing message headers.
# 
#               o      When prepending text before a message header
#                      line,  the  prepended text must begin with a
#                      valid message header label.
# 
#               o      This action cannot be used to prepend multi-
#                      line text.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#        REDIRECT user@domain
#               Write a message redirection request  to  the  queue
#               file,  and  inspect  the next input line. After the
#               message is queued, it will be sent to the specified
#               address instead of the intended recipient(s).
# 
#               Note:  this action overrides the FILTER action, and
#               affects all recipients of the message. If  multiple
#               REDIRECT  actions  fire,  only the last one is exe-
#               cuted.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#        REPLACE text...
#               Replace  the  current line with the specified text,
#               and inspect the next input line.
# 
#               This feature is available in Postfix 2.2 and later.
#               The  description below applies to Postfix 2.2.2 and
#               later.
# 
#               Notes:
# 
#               o      When replacing a message  header  line,  the
#                      replacement  text  must  begin  with a valid
#                      header label.
# 
#               o      The replaced text remains part of the  input
#                      stream.  Unlike  the result from the PREPEND
#                      action, a replaced  message  header  may  be
#                      subject  to address rewriting and may affect
#                      the way that Postfix  adds  missing  message
#                      headers.
# 
#        REJECT optional text...
#               Reject  the  entire  message.  Reply  with optional
#               text... when the optional text is specified, other-
#               wise reply with a generic error message.
# 
#               Note:   this  action  disables  further  header  or
#               body_checks inspection of the current  message  and
#               affects all recipients.
# 
#               Postfix version 2.3 and later support enhanced sta-
#               tus codes.  When no code is specified at the begin-
#               ning of optional text..., Postfix inserts a default
#               enhanced status code of "5.7.1".
# 
#        WARN optional text...
#               Log a warning with the optional text... (or  log  a
#               generic  message), and inspect the next input line.
#               This action is useful for debugging and for testing
#               a pattern before applying more drastic actions.
# 
# BUGS
#        Empty lines never match, because some map types mis-behave
#        when given a zero-length search string.   This  limitation
#        may  be  removed for regular expression tables in a future
#        release.
# 
#        Many people overlook the main limitations  of  header  and
#        body_checks rules.
# 
#        o      These  rules  operate on one logical message header
#               or one body line at a time. A decision made for one
#               line is not carried over to the next line.
# 
#        o      If  text  in the message body is encoded (RFC 2045)
#               then the rules need to be specified for the encoded
#               form.
# 
#        o      Likewise,  when  message  headers  are encoded (RFC
#               2047) then the rules need to be specified  for  the
#               encoded form.
# 
#        Message  headers added by the cleanup(8) daemon itself are
#        excluded from inspection. Examples of such message headers
#        are From:, To:, Message-ID:, Date:.
# 
#        Message  headers  deleted by the cleanup(8) daemon will be
#        examined before they are deleted. Examples are: Bcc:, Con-
#        tent-Length:, Return-Path:.
# 
# CONFIGURATION PARAMETERS
#        body_checks
#               Lookup tables with content filter rules for message
#               body lines.  These filters see one physical line at
#               a  time,  in  chunks  of at most $line_length_limit
#               bytes.
# 
#        body_checks_size_limit
#               The amount of  content  per  message  body  segment
#               (attachment) that is subjected to $body_checks fil-
#               tering.
# 
#        header_checks
# 
#        mime_header_checks (default: $header_checks)
# 
#        nested_header_checks (default: $header_checks)
#               Lookup tables with content filter rules for message
#               header  lines:  respectively,  these are applied to
#               the initial message  headers  (not  including  MIME
#               headers),  to the MIME headers anywhere in the mes-
#               sage, and to the initial headers of  attached  mes-
#               sages.
# 
#               Note:  these filters see one logical message header
#               at a time, even when a message header spans  multi-
#               ple  lines.  Message  headers  that are longer than
#               $header_size_limit characters are truncated.
# 
#        disable_mime_input_processing
#               While receiving mail, give no special treatment  to
#               MIME  related  message  headers; all text after the
#               initial message headers is considered to be part of
#               the  message body. This means that header_checks is
#               applied to all the  initial  message  headers,  and
#               that body_checks is applied to the remainder of the
#               message.
# 
#               Note: when used in this  manner,  body_checks  will
#               process  a  multi-line message header one line at a
#               time.
# 
# EXAMPLES
#        Header pattern to block attachments  with  bad  file  name
#        extensions.   For  convenience, the PCRE /x flag is speci-
#        fied, so that there is no need  to  collapse  the  pattern
#        into   a   single  line  of  text.   The  purpose  of  the
#        [[:xdigit:]] sub-expressions is to recognize Windows CLSID
#        strings.
# 
#        /etc/postfix/main.cf:
#            header_checks = pcre:/etc/postfix/header_checks.pcre
# 
#        /etc/postfix/header_checks.pcre:
#            /^Content-(Disposition|Type).*name\s*=\s*"?(.*(\.|=2E)(
#              ade|adp|asp|bas|bat|chm|cmd|com|cpl|crt|dll|exe|
#              hlp|ht[at]|
#              inf|ins|isp|jse?|lnk|md[betw]|ms[cipt]|nws|
#              \{[[:xdigit:]]{8}(?:-[[:xdigit:]]{4}){3}-[[:xdigit:]]{12}\}|
#              ops|pcd|pif|prf|reg|sc[frt]|sh[bsm]|swf|
#              vb[esx]?|vxd|ws[cfh]))(\?=)?"?\s*(;|$)/x
#                REJECT Attachment name "$2" may not end with ".$4"
# 
#        Body pattern to stop a specific HTML browser vulnerability
#        exploit.
# 
#        /etc/postfix/main.cf:
#            body_checks = regexp:/etc/postfix/body_checks
# 
#        /etc/postfix/body_checks:
#            /^<iframe src=(3D)?cid:.* height=(3D)?0 width=(3D)?0>$/
#                REJECT IFRAME vulnerability exploit
# 
# SEE ALSO
#        cleanup(8), canonicalize and enqueue Postfix message
#        pcre_table(5), format of PCRE lookup tables
#        regexp_table(5), format of POSIX regular expression tables
#        postconf(1), Postfix configuration utility
#        postmap(1), Postfix lookup table management
#        postsuper(1), Postfix janitor
#        postcat(1), show Postfix queue file contents
#        RFC 2045, base64 and quoted-printable encoding rules
#        RFC 2047, message header encoding for non-ASCII text
# 
# README FILES
#        Use "postconf readme_directory" or  "postconf  html_direc-
#        tory" to locate this information.
#        DATABASE_README, Postfix lookup table overview
#        CONTENT_INSPECTION_README, Postfix content inspection overview
#        BUILTIN_FILTER_README, Postfix built-in content inspection
#        BACKSCATTER_README, blocking returned forged mail
# 
# LICENSE
#        The  Secure  Mailer  license must be distributed with this
#        software.
# 
# AUTHOR(S)
#        Wietse Venema
#        IBM T.J. Watson Research
#        P.O. Box 704
#        Yorktown Heights, NY 10598, USA
# 
#                                                               HEADER_CHECKS(5)

header_checks_map

Wollen wir nun Nachrichten von bestimmten Absendern oder anderen Einträgen in den Headerzeilen generell blocken, so legen wir uns folgende Konfigurationsdatei /etc/postfix/header_checks_map an.

 # vim /etc/postfix/header_checks_map
/etc/postfix/header_checks_map
# Django : 2012-02-06                                                                                 
# Kapitel 13.5 Filtern von eMails nach Inhalt                                                         
# Kapitel 12.3 Überprüfen von Headern                                                                 
# In der Postfix-Konfigurationsdatei /etc/postfix/main.cf muss                                        
# body_checks = pcre:/etc/postfix/body_check_maps gesetzt sein!                                       
#                                                                                                     
# Nach dem Ändern der Datei ist ein "systemctl reload postfix.service" durchzuführen!                 
#                                                                                                     
# Die Nummern hinter dem REJECT tauchen später als SMTP-Error und auch im Mailserver-Log auf.         
# Die auslösende Filter-Regel, die den Block ausgelöst hat, ist somit leicht wieder zu finden.        
#                                                                                                     
 
# Ausnahmeregelung für den sicheren IT-/Mailbetrieb im heimischen Netzwerk
#                                                                         
# Domeus hat bis heute nicht den Unterschied zwischen Mailheader-To und   
# SMTP-Envelope-To verstanden und fabriziert seit nunmehr über sieben Jahren in
# schöner Regelmäßigkeit Mailschleifen im vier/fünfstelligen Bereich.          
#                                                                              
/^Received:.*domeus\.com/       REJECT Domeus baut Mailschleifen und hat wichtige RFCs nicht verstanden
#                                                                                                      
# Dauerhaft genutzte Regelungen:                                                                       
# ===============================================                                                      
# [Immer mit aufsteiger Nummer sauber eintragen!]                                                      
#                                                                                                      
If /^Subject:/i                                                                                        
/^Subject:.*Sicherheitsaktualisierung/                  REJECT Header-Subject-Spamschutzregel Subj-1071
/^Subject:.*PARTNERSHIP.*/                              REJECT Header-Subject-Spamschutzregel Subj-1070
/^Subject:.*TEMPORARY JOB OFFER.*/                      REJECT Header-Subject-Spamschutzregel Subj-1069
/^Subject:.*URGENT ATTENTION.*/                         REJECT Header-Subject-Spamschutzregel Subj-1068
/^Subject:.*Penis.*/                                    REJECT Header-Subject-Spamschutzregel Subj-1067
/^Subject:.*Potenzschwache.*/                           REJECT Header-Subject-Spamschutzregel Subj-1066
/^Subject:.*saxaelle.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1065
/^Subject:.*formula for men.*/                          REJECT Header-Subject-Spamschutzregel Subj-1064
/^Subject:.*wife happiness.*/                           REJECT Header-Subject-Spamschutzregel Subj-1063
/^Subject:.*rentiert sich.*/                            REJECT Header-Subject-Spamschutzregel Subj-1062
/^Subject:.*caught on camera./                          REJECT Header-Subject-Spamschutzregel Subj-1061
/^Subject:.*Betriebsstaette sucht Beschaeftigte.*/      REJECT Header-Subject-Spamschutzregel Subj-1060
/^Subject:.*Stimulate her.*/                            REJECT Header-Subject-Spamschutzregel Subj-1059
/^Subject:.*WITH DUE RESPECT.*/                         REJECT Header-Subject-Spamschutzregel Subj-1058
/^Subject:.*Bigger snake.*/                             REJECT Header-Subject-Spamschutzregel Subj-1057
/^Subject:.*Bang her.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1056
/^Subject:.*young and enhanced.*/                       REJECT Header-Subject-Spamschutzregel Subj-1055
/^Subject:.*YOUR ASSISTANCE.*/                          REJECT Header-Subject-Spamschutzregel Subj-1054
/^Subject:.*Helping people.*/                           REJECT Header-Subject-Spamschutzregel Subj-1053
/^Subject:.*Enhancing.*/                                REJECT Header-Subject-Spamschutzregel Subj-1052
/^Subject:.*Blaue Pillchen.*/                           REJECT Header-Subject-Spamschutzregel Subj-1051
/^Subject:.*Impotenz.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1050
/^Subject:.*ge.fi.ckt.*/                                REJECT Header-Subject-Spamschutzregel Subj-1049
/^Subject:.*Softshell.*/                                REJECT Header-Subject-Spamschutzregel Subj-1048
/^Subject:.*rollige Ramona.*/                           REJECT Header-Subject-Spamschutzregel Subj-1047
/^Subject:.*Dringende Gesch�ft.*/                       REJECT Header-Subject-Spamschutzregel Subj-1046
/^Subject:.*Se-xy.*/                                    REJECT Header-Subject-Spamschutzregel Subj-1045
/^Subject:.*private party.*/                            REJECT Header-Subject-Spamschutzregel Subj-1044
/^Subject:.*williges Teeny.*/                           REJECT Header-Subject-Spamschutzregel Subj-1043
/^Subject:.*Special Offer.*/                            REJECT Header-Subject-Spamschutzregel Subj-1042
/^Subject:.*LiveCams.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1041
/^Subject:.*gevoegelt.*/                                REJECT Header-Subject-Spamschutzregel Subj-1040
/^Subject:.*gefi.ckte.*/                                REJECT Header-Subject-Spamschutzregel Subj-1039
/^Subject:.*medications.*/                              REJECT Header-Subject-Spamschutzregel Subj-1038
/^Subject:.*Drecksstueck.*/                             REJECT Header-Subject-Spamschutzregel Subj-1037
/^Subject:.*Miststueck.*/                               REJECT Header-Subject-Spamschutzregel Subj-1036
/^Subject:.*verdorbene Hausfrau.*/                      REJECT Header-Subject-Spamschutzregel Subj-1035
/^Subject:.*Ficken.*/                                   REJECT Header-Subject-Spamschutzregel Subj-1034
/^Subject:.*verdorbene Schlampe.*/                      REJECT Header-Subject-Spamschutzregel Subj-1033
/^Subject:.*fi.ckbereit.*/                              REJECT Header-Subject-Spamschutzregel Subj-1032
/^Subject:.*immer feucht.*/                             REJECT Header-Subject-Spamschutzregel Subj-1031
/^Subject:.*lets chat.*/                                REJECT Header-Subject-Spamschutzregel Subj-1030
/^Subject:.*bumsbare.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1029
/^Subject:.*geiles Weib.*/                              REJECT Header-Subject-Spamschutzregel Subj-1028
/^Subject:.*Dild_o.*/                                   REJECT Header-Subject-Spamschutzregel Subj-1027
/^Subject:.*kommen einmal pro Stunde.*/                 REJECT Header-Subject-Spamschutzregel Subj-1026
/^Subject:.*secret to pleasuring.*/                     REJECT Header-Subject-Spamschutzregel Subj-1025
/^Subject:.*will schlucken.*/                           REJECT Header-Subject-Spamschutzregel Subj-1024
/^Subject:.*an-algeiles.*/                              REJECT Header-Subject-Spamschutzregel Subj-1023
/^Subject:.*impotence.*/                                REJECT Header-Subject-Spamschutzregel Subj-1022
/^Subject:.*deutscher Freund.*/                         REJECT Header-Subject-Spamschutzregel Subj-1021
/^Subject:.*Po-rno.*/                                   REJECT Header-Subject-Spamschutzregel Subj-1020
/^Subject:.*Entspannt 60 Minuten nicht kommen.*/        REJECT Header-Subject-Spamschutzregel Subj-1019
/^Subject:.*Never be small and tiny again.*/            REJECT Header-Subject-Spamschutzregel Subj-1018
/^Subject:.*Haben Sie wieder Spass am Leben.*/          REJECT Header-Subject-Spamschutzregel Subj-1017
/^Subject:.*D ildo.*/                                   REJECT Header-Subject-Spamschutzregel Subj-1016
/^Subject:.*chat with you.*/                            REJECT Header-Subject-Spamschutzregel Subj-1015
/^Subject:.*zu frueh kommen.*/                          REJECT Header-Subject-Spamschutzregel Subj-1014
/^Subject:.*aufgeschlossene Kontakte.*/                 REJECT Header-Subject-Spamschutzregel Subj-1013
/^Subject:.*Viagra.*/                                   REJECT Header-Subject-Spamschutzregel Subj-1012
/^Subject:.*gefic-kt.*/                                 REJECT Header-Subject-Spamschutzregel Subj-1011
/^Subject:.*Frau sucht aufgeschlossenen Mann.*/         REJECT Header-Subject-Spamschutzregel Subj-1010
/^Subject:.*Nach 10 Minuten kommen.*/                   REJECT Header-Subject-Spamschutzregel Subj-1009
/^Subject:.*Mann lebt nur einmal.*/                     REJECT Header-Subject-Spamschutzregel Subj-1008
/^Subject:.*You have received an eCard.*/               REJECT Header-Subject-Spamschutzregel Subj-1007
/^Subject:.*D.i.l.d.o.*/                                REJECT Header-Subject-Spamschutzregel Subj-1006
/^Subject:.*naturgeil.*/                                REJECT Header-Subject-Spamschutzregel Subj-1005
/^Subject:.*So werden sie von jeder Frau vergoettert!/  REJECT Header-Subject-Spamschutzregel Subj-1004
/^Subject:.*Advocacy.Notary Notice.*/                   REJECT Header-Subject-Spamschutzregel Subj-1003
/^Subject:.*Webcam Luder.*/                             REJECT Header-Subject-Spamschutzregel Subj-1002
/^Subject:.*Potenzprobleme.*/                           REJECT Header-Subject-Spamschutzregel Subj-1001
/^Subject:.*RedBull fur Ihr bestes Stueck/              REJECT Header-Subject-Spamschutzregel Subj-1000
Endif                                                                                                  
#                                                                                                      
# und das Ganze nach Header-From                                                                       
# ==============================                                                                       
#                                                                                                      
#If /^From:/i                                                                                          
#/^From: .*Online Spiele.*/                                     REJECT Header-From-Spamschutzregel From-106                                                                                                       
#/^From: .*Apotheken-News.*/                             REJECT Header-From-Spamschutzregel From-1005                                                                                                             
#/^From: .*Kasino.*/                                    REJECT Header-From-Spamschutzregel From-1004                                                                                                              
#/^From: .*Pharmacy.*/                                          REJECT Header-From-Spamschutzregel From-1003                                                                                                      
#/^From: .*Royal Club Casino.*/                          REJECT Header-From-Spamschutzregel From-1002    
#/^From: .*Euro Dice Casino.*/                           REJECT Header-From-Spamschutzregel From-1001    
#/^From:.*happydigits.de/                                REJECT Header-From-Spamschutzregel From-1000
#Endif
 
 
# Django : 2014-10-10
##If /^To:/i
##/^To: .*dj4n90@piraten-it.guru.*/                     456 I hob grod koan bock, vozupf de!
##Endif
#
# generelle Filerregelungen nach den üblichen Verdächtigen
# ========================================================
#
/^Date: .* 200[0-7]/                                    REJECT Your email has a date from the past. Fix your system clock and try again.
/^Date: .* 19[0-9][0-9]/                                REJECT Your email has a date from the past. Fix your system clock and try again.
If /^X-Mailer:/i
/^X-Mailer: 0001/                                       REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Avalanche/                                  REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Crescent Internet Tool/                     REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: DiffondiCool/                               REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: E-Mail Delivery Agent/                      REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Emailer Platinum/                           REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Entity/                                     REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Extractor/                                  REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: Floodgate/                                  REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: GOTO Software Sarbacane/                    REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: MailWorkz/                                  REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: MassE-Mail/                                 REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: MaxBulk.Mailer/                             REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: News Breaker Pro/                           REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: SmartMailer/                                REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: StormPort/                                  REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
/^X-Mailer: SuperMail-2/                                REJECT You used an email program that is used almost exclusively for spam. We do not accept email sent using this program.
Endif

body_checks_map

Wollen wir nun Nachrichten von bestimmten Absendern oder anderen Einträgen in den Headerzeilen generell blocken, so legen wir uns folgende Konfigurationsdatei /etc/postfix/body_checks_map an.

 # /etc/postfix/body_checks_map
/etc/postfix/body_checks_map
# Django : 2012-02-06
# Kapitel 13.5 Filtern von eMails nach Inhalt
# Kapitel 12.6 Body prüfen
# In der Postfix-Konfigurationsdatei /etc/postfix/main.cf muss
# body_checks = pcre:/etc/postfix/header_check_maps gesetzt sein!
#
# Nach dem Ändern der Datei ist ein "systemctl reload postfix.service" reload durchzuführen!
#
# Die Nummern hinter dem REJECT tauchen später als SMTP-Error und auch im Mailserver-Log auf.
# Die auslösende Filter-Regel, die den Block ausgelöst hat, ist somit leicht wieder zu finden.
#
 
#/.*http:\/\/www.csu.de:80\/.*/                  REJECT Body_Check_Rule_4_Dummies: 0002
#/.*was@qualys.com.*/                            REJECT Body_Check_Rule_4_Dummies: 0001

Aktivierung

Zum Aktivieren unserer Konfigurationsänderungen führen wir nun einen Reload unseres Postfix-Servers durch.

 # systemctl reload postfix.service

Bei Bedarf können wir uns noch vergewissern und prüfen welchen Status unser MX nun hat.

 # systemctl status postfix.service
postfix.service - Postfix Mail Transport Agent
   Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled)
   Active: active (running) since Mon 2014-11-10 20:57:24 CET; 1 day 17h ago
  Process: 15133 ExecStop=/usr/sbin/postfix stop (code=exited, status=0/SUCCESS)
  Process: 17334 ExecReload=/usr/sbin/postfix reload (code=exited, status=0/SUCCESS)
  Process: 15148 ExecStart=/usr/sbin/postfix start (code=exited, status=0/SUCCESS)
  Process: 15146 ExecStartPre=/usr/libexec/postfix/chroot-update (code=exited, status=0/SUCCESS)
  Process: 15143 ExecStartPre=/usr/libexec/postfix/aliasesdb (code=exited, status=0/SUCCESS)
 Main PID: 15221 (master)
   CGroup: /system.slice/postfix.service
           ├─15221 /usr/libexec/postfix/master -w
           ├─17345 qmgr -l -t unix -u
           └─17346 pickup -l -t unix -u

Nov 12 14:02:04 vml000087.dmz.nausch.org postfix/pickup[17257]: D0A24C00088: uid=0 from=<root>
Nov 12 14:02:04 vml000087.dmz.nausch.org postfix/cleanup[17292]: D0A24C00088: message-id=<20141112130...>
Nov 12 14:02:04 vml000087.dmz.nausch.org postfix/qmgr[15223]: D0A24C00088: from=<root@nausch.org>, s...e)
Nov 12 14:02:05 vml000087.dmz.nausch.org postfix/lmtp[17298]: D0A24C00088: to=<django@nausch.org>, o...d)
Nov 12 14:02:05 vml000087.dmz.nausch.org postfix/qmgr[15223]: D0A24C00088: removed
Nov 12 14:35:39 vml000087.dmz.nausch.org systemd[1]: Reloading Postfix Mail Transport Agent.
Nov 12 14:35:39 vml000087.dmz.nausch.org postfix/master[15221]: reload -- version 2.11.3, configurat...ix
Nov 12 14:35:39 vml000087.dmz.nausch.org systemd[1]: Reloaded Postfix Mail Transport Agent.
Nov 12 14:35:47 vml000087.dmz.nausch.org systemd[1]: Reloading Postfix Mail Transport Agent.
Nov 12 14:35:47 vml000087.dmz.nausch.org postfix/master[15221]: reload -- version 2.11.3, configurat...ix
Nov 12 14:35:47 vml000087.dmz.nausch.org systemd[1]: Reloaded Postfix Mail Transport Agent.
Hint: Some lines were ellipsized, use -l to show in full.

Links

1)
Perl Compatible Regular Expressions