Exiscan+clamav

From: Adam M Ryan (adam_at_fastservers.net)
Date: 11/16/04

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    Date: Mon, 15 Nov 2004 20:20:31 -0600
    
    

    Right now I am using Exim 4.43 and clamav-0.80_1 both installed from ports.
    I am trying to get clamav to scan incoming email. I have altered my exim
    configure file with the following:

    av_scanner=clamd:/var/run/clamav/clamd

       deny message = This message contains malware ($malware_name)
            demime = *
            malware = *

    I have also double checked everything in
    /usr/ports/mail/exim/files/POST-INSTALL-NOTES.clamd.

    But I still can't get my emailed scanned by clamav.

    Does anyone have a working configure file that they could post?

    Below is my version:

    Thanks!

    Adam

    -------------------------------------------------------

    ######################################################################
    # Runtime configuration file for Exim #
    ######################################################################

    # This is a default configuration file which will operate correctly in #
    uncomplicated installations. Please see the manual for a complete list # of
    all the runtime configuration options that can be included in a #
    configuration file. There are many more than are mentioned here. The #
    manual is in the file doc/spec.txt in the Exim distribution as a plain #
    ASCII file. Other formats (PostScript, Texinfo, HTML, PDF) are available #
    from the Exim ftp sites. The manual is also online at the Exim web sites.

    # This file is divided into several parts, all but the first of which are #
    headed by a line starting with the word "begin". Only those parts that # are
    required need to be present. Blank lines, and lines starting with # # are
    ignored.

    ########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ###########
    # #
    # Whenever you change Exim's configuration file, you *must* remember to #
    # HUP the Exim daemon, because it will not pick up the new configuration #
    # until you do. However, any other Exim processes that are started, for #
    # example, a process started by an MUA in order to send a message, will #
    # see the new configuration as soon as it is in place. #
    # #
    # You do not need to HUP the daemon for changes in auxiliary files that #
    # are referenced from this file. They are read every time they are used. #
    # #
    # It is usually a good idea to test a new configuration for syntactic #
    # correctness before installing it (for example, by running the command #
    # "exim -C /config/file.new -bV"). #
    # #
    ########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ###########

    ######################################################################
    # MAIN CONFIGURATION SETTINGS #
    ######################################################################

    # Specify your host's canonical name here. This should normally be the fully
    # qualified "official" name of your host. If this option is not set, the #
    uname() function is called to obtain the name. In many cases this does # the
    right thing and you need not set anything explicitly.

    # primary_hostname =

    # The next three settings create two lists of domains and one list of hosts.
    # These lists are referred to later in this configuration using the syntax #
    +local_domains, +relay_to_domains, and +relay_from_hosts, respectively. They
    # are all colon-separated lists:

    domainlist local_domains = @
    domainlist relay_to_domains =
    hostlist relay_from_hosts = localhost

    # Most straightforward access control requirements can be obtained by #
    appropriate settings of the above options. In more complicated situations,
    you # may need to modify the Access Control List (ACL) which appears later
    in this # file.

    # The first setting specifies your local domains, for example:
    #
    # domainlist local_domains = my.first.domain : my.second.domain
    #
    # You can use "@" to mean "the name of the local host", as in the default #
    setting above. This is the name that is specified by primary_hostname, # as
    specified above (or defaulted). If you do not want to do any local #
    deliveries, remove the "@" from the setting above. If you want to accept
    mail # addressed to your host's literal IP address, for example, mail
    addressed to # "user@[192.168.23.44]", you can add "@[]" as an item in the
    local domains # list. You also need to uncomment "allow_domain_literals"
    below. This is not # recommended for today's Internet.

    # The second setting specifies domains for which your host is an incoming
    relay.
    # If you are not doing any relaying, you should leave the list empty.
    However, # if your host is an MX backup or gateway of some kind for some
    domains, you # must set relay_to_domains to match those domains. For
    example:
    #
    # domainlist relay_to_domains = *.myco.com : my.friend.org # # This will
    allow any host to relay through your host to those domains.
    # See the section of the manual entitled "Control of relaying" for more #
    information.

    # The third setting specifies hosts that can use your host as an outgoing
    relay # to any other host on the Internet. Such a setting commonly refers to
    a # complete local network as well as the localhost. For example:
    #
    # hostlist relay_from_hosts = 127.0.0.1 : 192.168.0.0/16 # # The "/16" is a
    bit mask (CIDR notation), not a number of hosts. Note that you # have to
    include 127.0.0.1 if you want to allow processes on your host to send # SMTP
    mail by using the loopback address. A number of MUAs use this method of #
    sending mail.

    # All three of these lists may contain many different kinds of item,
    including # wildcarded names, regular expressions, and file lookups. See the
    reference # manual for details. The lists above are used in the access
    control list for # incoming messages. The name of this ACL is defined here:

    acl_smtp_rcpt = acl_check_rcpt

    # You should not change that setting until you understand how ACLs work.

    # The following ACL entries are used if you want to do content scanning with
    # the exiscan-acl patch. When you uncomment one of these lines, you must
    also # review the respective entries in the ACL section further below.

    # acl_smtp_mime = acl_check_mime
    # acl_smtp_data = acl_check_content

    # This configuration variable defines the virus scanner that is used with #
    the 'malware' ACL condition of the exiscan acl-patch. If you do not use #
    virus scanning, leave it commented. Please read doc/exiscan-acl-readme.txt #
    for a list of supported scanners.

    av_scanner = av_scanner=clamd:/var/run/clamav/clamd

    # The following setting is only needed if you use the 'spam' ACL condition #
    of the exiscan-acl patch. It specifies on which host and port the
    SpamAssassin # "spamd" daemon is listening. If you do not use this
    condition, or you use # the default of "127.0.0.1 783", you can omit this
    option.

    # spamd_address = 127.0.0.1 783

    # Specify the domain you want to be added to all unqualified addresses #
    here. An unqualified address is one that does not contain an "@" character #
    followed by a domain. For example, "caesar@rome.example" is a fully
    qualified # address, but the string "caesar" (i.e. just a login name) is an
    unqualified # email address. Unqualified addresses are accepted only from
    local callers by # default. See the recipient_unqualified_hosts option if
    you want to permit # unqualified addresses from remote sources. If this
    option is not set, the # primary_hostname value is used for qualification.

    # qualify_domain =

    # If you want unqualified recipient addresses to be qualified with a
    different # domain to unqualified sender addresses, specify the recipient
    domain here.
    # If this option is not set, the qualify_domain value is used.

    # qualify_recipient =

    # The following line must be uncommented if you want Exim to recognize #
    addresses of the form "user@[10.11.12.13]" that is, with a "domain literal"
    # (an IP address) instead of a named domain. The RFCs still require this
    form, # but it makes little sense to permit mail to be sent to specific
    hosts by # their IP address in the modern Internet. This ancient format has
    been used # by those seeking to abuse hosts by using them for unwanted
    relaying. If you # really do want to support domain literals, uncomment the
    following line, and # see also the "domain_literal" router below.

    # allow_domain_literals

    # No deliveries will ever be run under the uids of these users (a colon- #
    separated list). An attempt to do so causes a panic error to be logged, and
    # the delivery to be deferred. This is a paranoic safety catch. There is an
    # even stronger safety catch in the form of the FIXED_NEVER_USERS setting #
    in the configuration for building Exim. The list of users that it specifies
    # is built into the binary, and cannot be changed. The option below just
    adds # additional users to the list. The default for FIXED_NEVER_USERS is
    "root", # but just to be absolutely sure, the default here is also "root".

    # Note that the default setting means you cannot deliver mail addressed to
    root # as if it were a normal user. This isn't usually a problem, as most
    sites have # an alias for root that redirects such mail to a human
    administrator.

    exim_user = mailnull
    exim_group = mail
    never_users = root

    # The setting below causes Exim to do a reverse DNS lookup on all incoming #
    IP calls, in order to get the true host name. If you feel this is too #
    expensive, you can specify the networks for which a lookup is done, or #
    remove the setting entirely.

    host_lookup = *

    # The settings below, which are actually the same as the defaults in the #
    code, cause Exim to make RFC 1413 (ident) callbacks for all incoming SMTP #
    calls. You can limit the hosts to which these calls are made, and/or change
    # the timeout that is used. If you set the timeout to zero, all RFC 1413
    calls # are disabled. RFC 1413 calls are cheap and can provide useful
    information # for tracing problem messages, but some hosts and firewalls
    have problems # with them. This can result in a timeout instead of an
    immediate refused # connection, leading to delays on starting up an SMTP
    session.

    rfc1413_hosts = *
    rfc1413_query_timeout = 30s

    # By default, Exim expects all envelope addresses to be fully qualified,
    that # is, they must contain both a local part and a domain. If you want to
    accept # unqualified addresses (just a local part) from certain hosts, you
    can specify # these hosts by setting one or both of # #
    sender_unqualified_hosts = # recipient_unqualified_hosts = # # to control
    sender and recipient addresses, respectively. When this is done, #
    unqualified addresses are qualified using the settings of qualify_domain #
    and/or qualify_recipient (see above).

    # If you want Exim to support the "percent hack" for certain domains, #
    uncomment the following line and provide a list of domains. The "percent #
    hack" is the feature by which mail addressed to x%y@z (where z is one of #
    the domains listed) is locally rerouted to x@y and sent on. If z is not one
    # of the "percent hack" domains, x%y is treated as an ordinary local part.
    This # hack is rarely needed nowadays; you should not enable it unless you
    are sure # that you really need it.
    #
    # percent_hack_domains =
    #
    # As well as setting this option you will also need to remove the test # for
    local parts containing % in the ACL definition below.

    # When Exim can neither deliver a message nor return it to sender, it
    "freezes"
    # the delivery error message (aka "bounce message"). There are also other #
    circumstances in which messages get frozen. They will stay on the queue for
    # ever unless one of the following options is set.

    # This option unfreezes frozen bounce messages after two days, tries # once
    more to deliver them, and ignores any delivery failures.

    ignore_bounce_errors_after = 2d

    # This option cancels (removes) frozen messages that are older than a week.

    timeout_frozen_after = 7d

    ######################################################################
    # ACL CONFIGURATION #
    # Specifies access control lists for incoming SMTP mail #
    ######################################################################

    begin acl

    # This access control list is used for every RCPT command in an incoming #
    SMTP message. The tests are run in order until the address is either #
    accepted or denied.
    acl_check_content:

      # Reject virus infested messages.
      deny message = This message contains malware ($malware_name)
            malware = *

      # Always add X-Spam-Score and X-Spam-Report headers, using SA system-wide
    settings
      # (user "nobody"), no matter if over threshold or not.
      warn message = X-Spam-Score: $spam_score ($spam_bar)
            spam = nobody:true
      warn message = X-Spam-Report: $spam_report
            spam = nobody:true

      # Add X-Spam-Flag if spam is over system-wide threshold
      warn message = X-Spam-Flag: YES
           spam = nobody

      # Reject spam messages with score over 10, using an extra condition.
      deny message = This message scored $spam_score points. Congratulations!
            spam = nobody:true
            condition = ${if >{$spam_score_int}{100}{1}{0}}

      # finally accept all the rest
      accept

    acl_check_rcpt:

      # Accept if the source is local SMTP (i.e. not over TCP/IP). We do this by
      # testing for an empty sending host field.

      accept hosts = :

     
    ############################################################################
    #
      # The following section of the ACL is concerned with local parts that
    contain
      # @ or % or ! or / or | or dots in unusual places.
      #
      # The characters other than dots are rarely found in genuine local parts,
    but
      # are often tried by people looking to circumvent relaying restrictions.
      # Therefore, although they are valid in local parts, these rules lock them
      # out, as a precaution.
      #
      # Empty components (two dots in a row) are not valid in RFC 2822, but Exim
      # allows them because they have been encountered. (Consider local parts
      # constructed as "firstinitial.secondinitial.familyname" when applied to
      # someone like me, who has no second initial.) However, a local part
    starting
      # with a dot or containing /../ can cause trouble if it is used as part of
    a
      # file name (e.g. for a mailing list). This is also true for local parts
    that
      # contain slashes. A pipe symbol can also be troublesome if the local part
    is
      # incorporated unthinkingly into a shell command line.
      #
      # Two different rules are used. The first one is stricter, and is applied
    to
      # messages that are addressed to one of the local domains handled by this
      # host. It blocks local parts that begin with a dot or contain @ % ! / or
    |.
      # If you have local accounts that include these characters, you will have
    to
      # modify this rule.

      deny message = Restricted characters in address
              domains = +local_domains
              local_parts = ^[.] : ^.*[@%!/|]

      # The second rule applies to all other domains, and is less strict. This
      # allows your own users to send outgoing messages to sites that use
    slashes
      # and vertical bars in their local parts. It blocks local parts that begin
      # with a dot, slash, or vertical bar, but allows these characters within
    the
      # local part. However, the sequence /../ is barred. The use of @ % and !
    is
      # blocked, as before. The motivation here is to prevent your users (or
      # your users' viruses) from mounting certain kinds of attack on remote
    sites.

      deny message = Restricted characters in address
              domains = !+local_domains
              local_parts = ^[./|] : ^.*[@%!] : ^.*/\\.\\./
     
    ############################################################################
    #

      # Accept mail to postmaster in any local domain, regardless of the source,
      # and without verifying the sender.

      accept local_parts = postmaster
              domains = +local_domains

      # Deny unless the sender address can be verified.

      require verify = sender

     
    ############################################################################
    #
      # There are no checks on DNS "black" lists because the domains that
    contain
      # these lists are changing all the time. However, here are two examples of
      # how you could get Exim to perform a DNS black list lookup at this point.
      # The first one denies, while the second just warns.
      #
      # deny message = rejected because $sender_host_address is in a
    black list at $dnslist_domain\n$dnslist_text
      # dnslists = black.list.example
      #
      # warn message = X-Warning: $sender_host_address is in a black
    list at $dnslist_domain
      # log_message = found in $dnslist_domain
      # dnslists = black.list.example
     
    ############################################################################
    #

      # Accept if the address is in a local domain, but only if the recipient
    can
      # be verified. Otherwise deny. The "endpass" line is the border between
      # passing on to the next ACL statement (if tests above it fail) or denying
      # access (if tests below it fail).

      accept domains = +local_domains
              endpass
              verify = recipient

      # Accept if the address is in a domain for which we are relaying, but
    again,
      # only if the recipient can be verified.

      accept domains = +relay_to_domains
              endpass
              verify = recipient

      # If control reaches this point, the domain is neither in +local_domains
      # nor in +relay_to_domains.

      # Accept if the message comes from one of the hosts for which we are an
      # outgoing relay. Recipient verification is omitted here, because in many
      # cases the clients are dumb MUAs that don't cope well with SMTP error
      # responses. If you are actually relaying out from MTAs, you should
    probably
      # add recipient verification here.

      accept hosts = +relay_from_hosts

      # Accept if the message arrived over an authenticated connection, from
      # any host. Again, these messages are usually from MUAs, so recipient
      # verification is omitted.

      accept authenticated = *

      # Reaching the end of the ACL causes a "deny", but we might as well give
      # an explicit message.

      deny message = relay not permitted

    # These access control lists are used for content scanning with the
    exiscan-acl # patch. You must also uncomment the entries for acl_smtp_data
    and acl_smtp_mime # (scroll up), otherwise the ACLs will not be used.
    IMPORTANT: the default entries here # should be treated as EXAMPLES. You
    MUST read the file doc/exiscan-acl-spec.txt # to fully understand what you
    are doing ...

    acl_check_mime:

      # Decode MIME parts to disk. This will support virus scanners later.
      warn decode = default

      # File extension filtering.
      deny message = Blacklisted file extension detected
           condition = ${if match \
                            {${lc:$mime_filename}} \
                            {\N(\.exe|\.pif|\.bat|\.scr|\.lnk|\.com)$\N} \
                         {1}{0}}
      
      # Reject messages that carry chinese character sets.
      # WARNING: This is an EXAMPLE.
      deny message = Sorry, noone speaks chinese here
           condition = ${if eq{$mime_charset}{gb2312}{1}{0}}

      accept

      

    ######################################################################
    # ROUTERS CONFIGURATION #
    # Specifies how addresses are handled #
    ######################################################################
    # THE ORDER IN WHICH THE ROUTERS ARE DEFINED IS IMPORTANT! #
    # An address is passed to each router in turn until it is accepted. #
    ######################################################################

    begin routers

    # This router routes to remote hosts over SMTP by explicit IP address, #
    when an email address is given in "domain literal" form, for example, #
    <user@[192.168.35.64]>. The RFCs require this facility. However, it is #
    little-known these days, and has been exploited by evil people seeking # to
    abuse SMTP relays. Consequently it is commented out in the default #
    configuration. If you uncomment this router, you also need to uncomment #
    allow_domain_literals above, so that Exim can recognize the syntax of #
    domain literal addresses.

    # domain_literal:
    # driver = ipliteral
    # domains = ! +local_domains
    # transport = remote_smtp

    # This router routes addresses that are not in local domains by doing a DNS
    # lookup on the domain name. Any domain that resolves to 0.0.0.0 or to a #
    loopback interface address (127.0.0.0/8) is treated as if it had no DNS #
    entry. Note that 0.0.0.0 is the same as 0.0.0.0/32, which is commonly
    treated # as the local host inside the network stack. It is not 0.0.0.0/0,
    the default # route. If the DNS lookup fails, no further routers are tried
    because of # the no_more setting, and consequently the address is
    unrouteable.

    dnslookup:
      driver = dnslookup
      domains = ! +local_domains
      transport = remote_smtp
      ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
      no_more

    # The remaining routers handle addresses in the local domain(s).

    # This router handles aliasing using a linearly searched alias file with the
    # name /etc/aliases. When this configuration is installed automatically, #
    the name gets inserted into this file from whatever is set in Exim's #
    build-time configuration. The default path is the traditional /etc/aliases.
    # If you install this configuration by hand, you need to specify the correct
    # path in the "data" setting below.
    #
    ##### NB You must ensure that the alias file exists. It used to be the case
    ##### NB that every Unix had that file, because it was the Sendmail
    default.
    ##### NB These days, there are systems that don't have it. Your aliases
    ##### NB file should at least contain an alias for "postmaster".
    #
    # If any of your aliases expand to pipes or files, you will need to set # up
    a user and a group for these deliveries to run under. You can do # this by
    uncommenting the "user" option below (changing the user name # as
    appropriate) and adding a "group" option if necessary. Alternatively, you #
    can specify "user" on the transports that are used. Note that the transports
    # listed below are the same as are used for .forward files; you might want #
    to set up different ones for pipe and file deliveries from aliases.

    system_aliases:
      driver = redirect
      allow_fail
      allow_defer
      data = ${lookup{$local_part}lsearch{/etc/aliases}}
      user = mailnull
      group = mail
      file_transport = address_file
      pipe_transport = address_pipe

    # This router handles forwarding using traditional .forward files in users'
    # home directories. If you want it also to allow mail filtering when a
    forward # file starts with the string "# Exim filter" or "# Sieve filter",
    uncomment # the "allow_filter" option.

    # If you want this router to treat local parts with suffixes introduced by
    "-"
    # or "+" characters as if the suffixes did not exist, uncomment the two
    local_ # part_suffix options. Then, for example, xxxx-foo@your.domain will
    be treated # in the same way as xxxx@your.domain by this router. You
    probably want to make # the same change to the localuser router.

    # The no_verify setting means that this router is skipped when Exim is #
    verifying addresses. Similarly, no_expn means that this router is skipped if
    # Exim is processing an EXPN command.

    # The check_ancestor option means that if the forward file generates an #
    address that is an ancestor of the current one, the current one gets #
    passed on instead. This covers the case where A is aliased to B and B # has
    a .forward file pointing to A.

    # The three transports specified at the end are those that are used when #
    forwarding generates a direct delivery to a file, or to a pipe, or sets # up
    an auto-reply, respectively.

    userforward:
      driver = redirect
      check_local_user
    # local_part_suffix = +* : -*
    # local_part_suffix_optional
      file = $home/.forward
    # allow_filter
      no_verify
      no_expn
      check_ancestor
      file_transport = address_file
      pipe_transport = address_pipe
      reply_transport = address_reply
      condition = ${if exists{$home/.forward} {yes} {no} }

    # This router matches local user mailboxes. If the router fails, the error #
    message is "Unknown user".

    # If you want this router to treat local parts with suffixes introduced by
    "-"
    # or "+" characters as if the suffixes did not exist, uncomment the two
    local_ # part_suffix options. Then, for example, xxxx-foo@your.domain will
    be treated # in the same way as xxxx@your.domain by this router.

    localuser:
      driver = accept
      check_local_user
    # local_part_suffix = +* : -*
    # local_part_suffix_optional
      transport = local_delivery
      cannot_route_message = Unknown user

    ######################################################################
    # TRANSPORTS CONFIGURATION #
    ######################################################################
    # ORDER DOES NOT MATTER #
    # Only one appropriate transport is called for each delivery. #
    ######################################################################

    # A transport is used only when referenced from a router that successfully #
    handles an address.

    begin transports

    # This transport is used for delivering messages over SMTP connections.

    remote_smtp:
      driver = smtp

    # This transport is used for local delivery to user mailboxes in traditional
    # BSD mailbox format. By default it will be run under the uid and gid of the
    # local user, and requires the sticky bit to be set on the /var/mail
    directory.
    # Some systems use the alternative approach of running mail deliveries under
    a # particular group instead of using the sticky bit. The commented options
    below # show how this can be done.

    local_delivery:
      driver = appendfile
      file = /var/mail/$local_part
      delivery_date_add
      envelope_to_add
      return_path_add
      group = mail
      user = $local_part
      mode = 0660
      no_mode_fail_narrower

    # This transport is used for handling pipe deliveries generated by alias or
    # .forward files. If the pipe generates any standard output, it is returned
    # to the sender of the message as a delivery error. Set return_fail_output #
    instead of return_output if you want this to happen only when the pipe fails
    # to complete normally. You can set different transports for aliases and #
    forwards if you want to - see the references to address_pipe in the routers
    # section above.

    address_pipe:
      driver = pipe
      return_output

    # This transport is used for handling deliveries directly to files that are
    # generated by aliasing or forwarding.

    address_file:
      driver = appendfile
      delivery_date_add
      envelope_to_add
      return_path_add

    # This transport is used for handling autoreplies generated by the filtering
    # option of the userforward router.

    address_reply:
      driver = autoreply

    ######################################################################
    # RETRY CONFIGURATION #
    ######################################################################

    begin retry

    # This single retry rule applies to all domains and all errors. It specifies
    # retries every 15 minutes for 2 hours, then increasing retry intervals, #
    starting at 1 hour and increasing each time by a factor of 1.5, up to 16 #
    hours, then retries every 6 hours until 4 days have passed since the first #
    failed delivery.

    # Address or Domain Error Retries
    # ----------------- ----- -------

    * * F,2h,15m; G,16h,1h,1.5; F,4d,6h

    ######################################################################
    # REWRITE CONFIGURATION #
    ######################################################################

    # There are no rewriting specifications in this default configuration file.

    begin rewrite

    ######################################################################
    # AUTHENTICATION CONFIGURATION #
    ######################################################################

    # There are no authenticator specifications in this default configuration
    file.

    begin authenticators

    ######################################################################
    # CONFIGURATION FOR local_scan() #
    ######################################################################

    # If you have built Exim to include a local_scan() function that contains #
    tables for private options, you can define those options here. Remember to #
    uncomment the "begin" line. It is commented by default because it provokes #
    an error with Exim binaries that are not built with LOCAL_SCAN_HAS_OPTIONS #
    set in the Local/Makefile.

    # begin local_scan

    # End of Exim configuration file

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