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== Virus & executable content blocking tutorial for qpsmtpd ==
{{Level|Advanced}}
==Email Attachments Virus & Executable content blocking==
The functionality to block possible executable and virus files attached to emails has been incorporated into SME Server v7.x. See the [[SME_Server:Documentation:Administration_Manual:Chapter13#E-mail_Filtering|Email]] panel in server manager.
===Problem===
===Problem===
Your SME Server receives a lot of email with virus infected attachments and you want to reject it before it enters your server's mail system. You want to block email with certain types of file attachments to improve security of your server or reduce bandwidth use caused by unwanted or undesired large multimedia files. Current methods typically use Anti Virus detection software, which are processor & memory intensive.
Your sme server receives a lot of email with virus infected attachments and you want to reject it before it enters your server's mail system. You want to block email with certain types of file attachments to improve security of your server or reduce bandwidth use caused by unwanted or undesired large multimedia files. Current methods typically use Anti Virus detection software, which are processor & memory intensive.
===Solution===
===Solution===
This functionality allows incoming and outgoing messages to be rejected if the attached file has executable content, which matches specific file type patterns. A default pattern matching database is created with common executable file patterns, which cover the majority of currently known Windows type executable viruses. Patterns can be created for any file types to allow multimedia or other attachments to be rejected where the system management policy considers it appropriate.
Email messages are rejected if the attachment content matches an entry in the patterns database. By default this includes the majority of *.exe files, older v1.0 *.zip files and some *.gif files. This blocking applies to both incoming and outgoing smtp email messages, including the local network, in order to stop virus propagation. If these file types need to be sent using email, they should be compressed using WinZip (v2.0 format) or WinRAR or other suitable compression software, or alternatively shared on the local network use file sharing. Note that recent releases of compression software use the v2.0 zip format.
Email messages are rejected if the attachment content matches an entry in the patterns database. By default this includes the majority of *.exe files, older v1.0 *.zip files and some *.gif files. This blocking applies to both incoming and outgoing smtp email messages, including the local network, in order to stop virus propagation. If these file types need to be sent using email, they should be compressed using WinZip (v2.0 format) or WinRAR or other suitable compression software, or alternatively shared on the local network use filesharing. Note that recent releases of compression software use the v2.0 zip format.
Messages with attachments that match the patterns database are rejected by the mail system, and as a result there is no further processing. In practice a large number of virus infected messages will be rejected, perhaps 95 % or more, depending on the type of virus infections you receive and your system exposure (email addresses).
Messages with attachments that match the patterns database are rejected by the mail system, and as a result there is no further processing. In practice a large number of virus infected messages will be rejected, perhaps 95 % or more, depending on the type of virus infections you receive and your system exposure (email addresses).
In conjunction with RBL list blocking of spam messages you can expect a reduction in virus detections by Clamavis from typically hundreds per month to one message per month. The use of RBL list spam blocking also helps reduce virus infected email messages entering the server, probably due to the fact that some virus infected messages come from similar sources as spam messages.
In conjunction with Real-time Blackhole List (RBL) blocking of spam messages you can expect the reduction in virus detections by ClamAV is from typically hundreds per month to one message per month. The use of RBL list spam blocking also helps reduce virus infected email messages entering the server, probably due to the fact that some virus infected messages come from similar sources as spam messages.
This method works for servers configured as either Server & Gateway or Server Only as long as the mail server components are enabled (qpsmtp & qmail) and the server has access to the Internet via another sme server or firewall.
This method works for servers configured as either Server & Gateway or Server Only as long as the mail server components are enabled (qpsmtp & qmail) and the server has access to the Internet via another SME Server or firewall.
===Additional Information===
===Additional Information===
Pattern matching acts as a "gross filter" to reject many known virus types, but a regularly updated virus scanner is still required to catch new viruses. Once these new executable content viruses have been analysed, additional patterns can be created and added to the patterns database as required. It is envisaged that new patterns would be added infrequently.
Pattern matching acts as a "gross filter" to reject many known virus types, but a regularly updated virus scanner is still required to catch new viruses. Once these new executable content viruses have been analysed, additional patterns can be created and added to the patterns database as required. It is envisaged that new patterns would be added infrequently.
This pattern matching feature should be used in conjunction with virus scanning software and spam filtering software, although these programs will have a lot less work to do. Pattern blocking should be compatible with other brands of virus & spam software based programs. They generally scan or filter the message after it has been accepted by the servers mail system. Pattern blocking occurs before the message is accepted, and if a matching occurs the message is rejected so it would never be scanned by secondary software based systems. Incompatibilities are therefore unlikely.
This pattern matching feature should be used in conjunction with virus scanning software and spam filtering software, although these programs will have a lot less work to do. Pattern blocking should be compatible with other brands of virus & spam software based programs. They generally scan or filter the message after it has been accepted by the servers mail system. Pattern blocking occurs before the message is accepted, and if a matching occurs the message is rejected so it would never be scanned by secondary software based systems. Incompatibilities are therefore unlikely.
Additional patterns can be added to the database after install is completed. Also see separate section below for information on analysing, creating & adding patterns.
An additional feature recommended to implement is [[:SME_Server:Documentation:FAQ#Real-time_Blackhole_List_.28RBL.29|RBL List blocking]] using qpsmtp, to reject spam messages from senders that are included on RBL lists. This technique will dramatically reduce the amount of spam entering the server. You should also consider the additional [[:SME_Server:Documentation:FAQ#Spam|Spam Blocking]] measures generally
{{Warning box|Enable additional patterns with care. Verify that the patterns do not block attachment types that you wish to receive.}}
===Enabling Pattern Matching===
===Enabling Pattern Matching===
There is a menu box in the server manager [[SME_Server:Documentation:Administration_Manual:Chapter13#E-mail_Filtering|Email panel]] which allows executable content blocking to be enabled or disabled. It is disabled by default. Use "Ctrl click" to highlight or un-highlight the various groups of file types, and then click the Save button to enable/disable pattern matching.
===Analyzing and creating patterns===
===Analyzing and creating patterns===
====Common file patterns (or signatures or magic)====
====Common file patterns (or signatures or magic)====
The standard patterns enabled by default are:
The standard patterns enabled by default are:
Windows executables seen in active viruses
Windows executables seen in active viruses
TVqQAAMAA
*TVqQAAMAA
TVpQAAIAA
*TVpQAAIAA
Additional Windows executable signatures not yet seen in viruses
Additional Windows executable signatures not yet seen in viruses
TVpAALQAc
*TVpAALQAc
TVpyAXkAX
*TVpyAXkAX
TVrmAU4AA
*TVrmAU4AA
TVrhARwAk
*TVrhARwAk
TVoFAQUAA
*TVoFAQUAA
TVoAAAQAA
*TVoAAAQAA
TVoIARMAA
*TVoIARMAA
TVouARsAA
*TVouARsAA
TVrQAT8AA
*TVrQAT8AA
TVoAAAEAAA
*TVoAAAEAAA
ZIP file signature seen in SoBig.E and mydoom
ZIP file signature seen in SoBig.E and mydoom
UEsDBAoAA (this pattern is blocked - zip v1.0 format)
*UEsDBAoAA (this pattern is blocked - zip v1.0 format)
UEsDBBQAA (this pattern is NOT blocked by default - zip v2.0 format
*UEsDBBQAA (this pattern is NOT blocked by default - zip v2.0 format
{{Note box|msg=If you block the zip v2.0 attachments, e-mail with OpenOffice documents (.odt) attached might be blocked as well, see also [[bugzilla:6045]].}}
GIF file found in a previous Microsoft virus
GIF file found in a previous Microsoft virus
R0lGODlhaAA7APcAAP///+rp6puSp6GZrDUjUUc6Zn53mFJMdbGvvVtXh2xre8bF1x8cU4yLprOy
*R0lGODlhaAA7APcAAP///+rp6puSp6GZrDUjUUc6Zn53mFJMdbGvvVtXh2xre8bF1x8cU4yLprOy
TVoAAD8AA
A recent pattern identified for the Worm.SomeFool.P virus
*TVoAAD8AA
Identified as MS-DOS executable
(Identified as MS-DOS executable)
====Extra patterns====
====Extra patterns====
Extra patterns not included in default database that may be enabled if required for blocking of multimedia files etc (long & short versions listed)
Extra patterns not included in the default database that may be enabled if required for blocking of multimedia files etc (long & short versions listed)
{{Note box|These have not been thoroughly tested and may need further refinement to ensure they accurately represent the signature pattern for all occurrences of the particular file type}}
Note that these have not been thoroughly tested and may need further refinement to ensure they accurately represent the signature pattern for all occurrences of the particular file type
SCR screen saver files - MS-DOS executable (EXE)
SCR screen saver files - MS-DOS executable (EXE)
*Example: TVqQAAMAAAAEAAAA//8AALgAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Example: TVqQAAMAAAAEAAAA//8AALgAAAAAAAAAQAAAAAAAAAAAAA
*Pattern: TVqQAAMAAA
Pattern: TVqQAAMAAA
PIF1 - data
PIF1 - data
*Example: AHhUYXggMTk5OCAgICAgICAgICAgICAgICAgICAgICCAAgAAWTpcSFNPRlRcSFQ5OFxIVDk4LkVY
Example: AHhUYXggMTk5OCAgICAgICAgICAgICAgICAgICAgICCAAgAAWTpcSFN
*Pattern: AHhUYXgg
Pattern: AHhUYXgg
PIF2 - data
PIF2 - data
Example: AMlIbDk5LmV4ZSAgICAgICAgICAgICAgICAgICAgICCAAIAAVDpccH
*Example: AMlIbDk5LmV4ZSAgICAgICAgICAgICAgICAgICAgICCAAIAAVDpccHJpdmF0ZVxIc29mdFxITFxI
*Pattern: AMlIbDk5Lm
Pattern: AMlIbDk5Lm
PIF3 - data
PIF3 - data
*Example: AHhIYW5kaVJlZ2lzdGVyIDIwMDAgICAgICAgICAgICCAAgAAWTpcSHNvZnRcSFJcSFIwMC5FWEUA
Example: AHhIYW5kaVJlZ2lzdGVyIDIwMDAgICAgICAgICAgICCAAgAAWTpcSHNvZn
*Pattern: AHhIYW5k
Pattern: AHhIYW5k
WAV sound file - data
WAV sound file - data
Example: UklGRiRwLgBXQVZFZm10IBAAAAABAAIAgLsAAADuAgAEABAAZGF0YQB
*Example: UklGRiRwLgBXQVZFZm10IBAAAAABAAIAgLsAAADuAgAEABAAZGF0YQBwLgAAAAAAAAAAAAAAAAAA
*Pattern: Uk1GRiRwL
Pattern: Uk1GRiRwL
JPEG image data, JFIF standard 0.00, aspect ratio, 0 x 0
JPEG image data, JFIF standard 0.00, aspect ratio, 0 x 0
Example: /9j/4AAQSkZJRgABAgEBLAEsAAD/7RLSUGhvdG9zaG9wIDMuMAA4QklNA+0
*Example: /9j/4AAQSkZJRgABAgEBLAEsAAD/7RLSUGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABABLAAAAAEA
*Pattern: /9j/4AAQSkZJRg
Pattern: /9j/4AAQSkZJRg
TIF - TIFF image data, little-endian
TIF - TIFF image data, little-endian
Example: SUkqAAgAAAAQAP4ABAABAAAAAAAAAAABAwABAAAAJgMAAAEBAwABAAAA
*Example: SUkqAAgAAAAQAP4ABAABAAAAAAAAAAABAwABAAAAJgMAAAEBAwABAAAAQAUAAAIBAwADAAAAzgAA
*Pattern: SUkqAAgAAAA
Pattern: SUkqAAgAAAA
PPT powerpoint presentation -Microsoft Office Document
PPT powerpoint presentation -Microsoft Office Document
Example: 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAAAAA
*Example: 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAAAAADEAwAAIRgBAAAAAAAA
*Pattern: 0M8R4KGxGuEA
Pattern: 0M8R4KGxGuEA
WMV Windows Media Player video file - Microsoft ASF
WMV Windows Media Player video file - Microsoft ASF
Example: MCaydY5mzxGm2QCqAGLObH8PAAAAAAAACwAAAAECodyrjEepzxGO5
*Example: MCaydY5mzxGm2QCqAGLObH8PAAAAAAAACwAAAAECodyrjEepzxGO5ADADCBTZWgAAAAAAAAAeeIB
*Pattern: MCaydY5mzxGm
Pattern: MCaydY5mzxGm
MPG mpeg1 video file - MPEG system stream data
MPG mpeg1 video file - MPEG system stream data
*Example: AAABuiEAAQAHgCgdAAABuwAMgCgdBeH/4OAuwMAgAAAB4AfcYC4xAAGMUREAAXAxAAABsxYBIIME
Example: AAABuiEAAQAHgCgdAAABuwAMgCgdBeH/4OAuwMAgAAAB4AfcYC4xAA
*Pattern: AAABuiEAAQAHg
Pattern: AAABuiEAAQAHg
M2P mpeg2 video file - MPEG system stream data
M2P mpeg2 video file - MPEG system stream data
*Example: AAABukQABAAGBQFG//gAAAG7AAyAo38F4X/g4OfAwCAAAAHgB9qAwQ0xAAG2QxEAAZojHmDnAAAB
Example: AAABukQABAAGBQFG//gAAAG7AAyAo38F4X/g4OfAwCAAAAHgB9qAw
*Pattern: AAABukQABAAGB
Pattern: AAABukQABAAGB
AVI video file - RIFF (little-endian) data
AVI video file - RIFF (little-endian) data
*Example: UklGRpC0qQBBVkkgTElTVDYBAABoZHJsYXZpaDgAAABAnAAA5MJnAAAAAAAQAAEAWggAAAAAAAAC
*Pattern: UklGRpC0qQBB
===Determining file pattern, signature or magic===
To find out what the pattern or signature or magic for a file is, it needs to be run through a base64 encoding routine and the appropriate strings determined from the first line of the output. That is, for "sane" files which have "magic" numbers at the start. The file can also be decoded to find out what type of it is. Published file specifications (where available) could also be referred to.
===Determining file pattern signature or magic===
To find out what the pattern or signature or magic for a file is, we need to run it through a base64 encoding routine and look for the appropriate strings in the first line of the output. That is, for "sane" files which have "magic" numbers at the start. We also can decode the file to find out what type of file it is. Published file specifications (where available) could also be referred to.
Copy a file to a folder on your sme server, say filename.zip
Copy a file to a folder on SME Server, say ''filename.zip''
At the command prompt do
At the command prompt do
perl -MMIME::Base64 -0777 -ne 'print encode_base64($_)' <filename.zip | head -1
This gives an output of
UEsDBAoAAQAAAMBOfzC356fxzVUAAMFVAAANAAAAZWxhaXZrZHVwLnNjckwHjDHTKYSGUE+SV
UEsDBAoAAQAAAMBOfzC356fxzVUAAMFVAAANAAAAZWxhaXZrZHVwLnNjckwHjDHTKYSGUE+SV
A suitable substring needs to be picked to use as the pattern for this file type, for example:
UEsDBAoAA
The pattern string needs to be long enough to avoid "false positives" and short enough to catch all of that file type. Running the above command across a few files of a particular type will usually clearly show the appropriate substring.
echo 'UEsDBAoAA' | perl -MMIME::Base64 -0777 -ne 'print decode_base64($_)' >/tmp/17.exe
To find out the file type details
echo 'UEsDBAoAA' | perl -MMIME::Base64 -0777 -ne 'print decode_base64($_)' >/tmp/17.exe
then run "file" on the result
then run "file" on the result
file /tmp/17.exe
file /tmp/17.exe
the output is
the output is
/tmp/17.exe: Zip archive data, at least v1.0 to extract
/tmp/17.exe: Zip archive data, at least v1.0 to extract
which identifies the type of file
which identifies the type of file
An alternative way of identifying the file pattern or signature for users of Clamavis-ng is to view the quarantined messages in /var/spool/amavis-ng/quarantine
An alternative way of identifying the file pattern or signature for users of Clamavis-ng is to view the quarantined messages in /var/spool/amavis-ng/quarantine
Here is an extract from a quarantined infected message that mimics a zip file
Here is an extract from a quarantined infected message that mimics a zip file
File: 406a8bee~aad.msg Col 0 30787 bytes
----------mtohkeqkmfnipbfntepj
Content-Type: application/octet-stream; name="AttachedFile.zip"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="AttachedFile.zip"
UEsDBAoAAQAAAMBOfzC356fxzVUAAMFVAAANAAAAZWxhaXZrZHVwLnNjckwHjDHTKYSGUE+SV1OwspplLsSWrbYvwOvHVHYOYDOiVliyLlDWU2LYVELdEiwxkwOPVsk3+m/Ddl9U56v6+tbrdXPEBTv+yEH56h/R+Bbk54hUOLieVPW61QOD7YVXZilxgCAZ+SppPxWuKv2iCBuw5qQ5N/r7CISrWWEPaAzGYwUmuERoNMEo4TFm6yV2BqBhv+Y1e/SLz30EV6anGmvwvKiWaLfcjo8sfF3UDQ203TAV33kypvZDqAsF/g3O1rvbEf+K/pZpWjOy1A5S3OWF7IKsbNxQdwqWPvuO6XS6QHwLQAF+6q4LKdUFM89j+lnKR3bXaGU3v18YN862XIeJtEqW3Ulbj8MA33IBDoTQzpYQwGQm+?????????..
So to create a new pattern for this message use
UEsDBAoAA
which is the pattern corresponding to ZIPV1 file type
which is the pattern corresponding to ZIPV1 file type
UEsDBAoAA: Zip archive data, at least v1.0 to extract
===Enabling or disabling patterns===
====Mailpatterns DB File====
The definitions and patterns etc for the various file types are stored in the SME Server configuration database file ''mailpatterns''. The property fields in the database for each defined file type are:
*pattern key - the type of the entry in the database (currently only the "pattern" type is used)
*Body - the substring to match
*Description - free format text to describe this pattern. This text will be used to display a menu of patterns to enable/disable in a later version
*Glob - whether to apply a wildcard match after the pattern
*LineStart - whether to only match this pattern at the start of the line
*Status - whether this pattern is currently enabled (i.e. blocked)
In general, to add a pattern to the database for a file with pattern <Signature> and file type <XYZ>, and enable it
/sbin/e-smith/db mailpatterns set <Signature> pattern Body <Signature> Description "<XYZ> file <Signature>)" Glob yes LineStart yes Status enabled
signal-event email-update
To disable the pattern do:
/sbin/e-smith/db mailpatterns setprop <FILETYPE> Status disabled
signal-event email-update
/sbin/e-smith/db mailpatterns set EXEFILES pattern Body TVqQAAMAA,TVpQAAIAA,
Some specific examples follow.
====Executable Type Files====
To add a pattern to the existing Executable type files (which should be done if new patterns are discovered for common new MSDOS Executable type viruses)
A pattern analysed from an email message received is
TVoAAD8AA
To add this to the db entries and enable it do:
/sbin/e-smith/db mailpatterns set TVoAAD8AA pattern Body TVoAAD8AA Description "PC executables (TVoAAD8AA)" Glob yes LineStart yes Status enabled
signal-event email-update
To check the entry is correct do:
To check the entry is correct do:
/sbin/e-smith/db mailpatterns show TVoAAD8AA
db mailpatterns show EXEFILES
which gives an output of
which gives an output of
TVoAAD8AA=pattern
Body=TVoAAD8AA
Description=PC executables (TVoAAD8AA)
Glob=yes
LineStart=yes
Status=enabled
====PIF2 Type Files====
To enable the pattern for PIF2 type files (which should be done to block some PIF attachments)
A pattern being tested for this file type is
A pattern being tested for this file type is
AMlIbDk5Lm
To add this to the db entries and enable it do:
/sbin/e-smith/db mailpatterns set AMlIbDk5Lm pattern Body AMlIbDk5Lm Description "PIF2 file (AMlIbDk5Lm)" Glob yes LineStart yes Status enabled
signal-event email-update
db mailpatterns set PIF2 pattern Body AMlIbDk5Lm Description "PIF2 data" Glob yes LineStart yes Status enabled
signal-event email-update
To check the entry is correct do:
To check the entry is correct do:
/sbin/e-smith/db mailpatterns show PIF2
db mailpatterns show PIF2
which gives an output of
which gives an output of
AMlIbDk5Lm=pattern
Body=AMlIbDk5Lm
Description=PIF2 file (AMlIbDk5Lm)
Glob=yes
LineStart=yes
Status=enabled
====Modifying the default database====
An alternative approach is to modify the default patterns loaded in the configuration database.
''initialize-default-databases'' loads the db with fragments from ''/etc/e-smith/db''. When new patterns are added to the master rpm, new fragments are also added.
Taking the PIF2 example above, to add a pattern to the default set do:
mkdir -p /etc/e-smith/db/mailpatterns/defaults/AMlIbDk5Lm/
and in that directory, create the following files with content shown:
type pattern
Body AMlIbDk5Lm
Description PIF2 file (AMlIbDk5Lm)
Glob yes
Status enabled
and in that directory, create the following files/contents:
type/pattern
Body/AMlIbDk5Lm
Description/PIF2 data
Glob/yes
Status/enabled
then do
then do
/etc/e-smith/events/actions/initialize-default-databases
/etc/e-smith/events/actions/initialize-default-databases
which will load the default settings
which will load the default settings
To show all the patterns in the mailpatterns database & their status (enabled or disabled) do
To show all the patterns in the mailpatterns database & their status (enabled or disabled) do
/sbin/e-smith/db mailpatterns show
===Checking logs===
Check logs for the effectiveness of blocking messages with executable content in the attachments
Note that you will only see these types of entries after blocking has been enabled and messages have been rejected.
By reviewing ''/var/log/qpsmtpd/current'' and ''/var/log/qpsmtpd/*'' entries for rejected messages can be seen with generally enough information as to why the rejection occurred, and therefore the effectiveness of Pattern Matching blocking.
{{Note box|Entries will only be seen after blocking has been enabled and messages have been rejected.}}
If you do not see all of the types of entries shown below, it would either be due to not having the particular Pattern enabled or not receiving attachments with that type of content.
If all of the types of entries shown below are not seen, it will either be due to not having the particular Pattern enabled or not receiving attachments with that type of content.
Date formatted logs can be viewed using the Server Manager ''View log files'' panel
To see ALL the log entries do
To see ALL the log entries do
grep "" /var/log/qpsmtpd/current | tai64nlocal
grep "" /var/log/qpsmtpd/current | tai64nlocal
To see only the rejected message entries and the reason for rejection do
To see only the rejected message entries and the reason for rejection do
grep "We don't accept email with executable content" /var/log/qpsmtpd/current | tai64nlocal
grep "We don't accept email with executable content" /var/log/qpsmtpd/current | tai64nlocal
Here is an example of some typical entries
Here is an example of some typical entries
2004-04-15 12:32:11.892522500 qpsmtp[23392]: 554 We don't accept email with executable content ZIPV1 (#5.3.4)
2004-04-15 15:23:40.765202500 qpsmtp[28963]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:08.132041500 qpsmtp[29241]: 554 We don't accept email with executable content EXE12 (#5.3.4)
2004-04-15 15:33:09.021650500 qpsmtp[29265]: 554 We don't accept email with executable content PIF (#5.3.4)
Alternatively filter on the pattern type code to see how many messages with a particular type of executable content are being rejected
grep EXE01 /var/log/qpsmtpd/current | tai64local
2004-04-15 15:23:40.765202500 qpsmtp[28963]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:08.132041500 qpsmtp[29241]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:09.021650500 qpsmtp[29265]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:24.986426500 qpsmtp[29274]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:23:40.765202500 qpsmtp[28963]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:08.132041500 qpsmtp[29241]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:09.021650500 qpsmtp[29265]: 554 We don't accept email with executable content EXE01 (#5.3.4)
2004-04-15 15:33:24.986426500 qpsmtp[29274]: 554 We don't accept email with executable content EXE01 (#5.3.4)
===Web sites for background information===
===Web sites for background information===
These links may be of interest. Note that they do not specifically apply to SME Server, so DO NOT implement them. They are listed for background information only.
*http://qmail.planetmirror.com/top.html
*http://qmail.planetmirror.com/top.html#microsoft
*http://qmail.planetmirror.com/qmail-smtpd-viruscan-1.3.patch
http://qmail.planetmirror.com/top.html
===Prior version of this Howto for sme6.x===
Here is a link to an earlier [http://mirror.contribs.org/smeserver/contribs/rmitchell/smeserver/howto/Virus%20and%20file%20blocking%20HOWTO%20using%20smtpfront-qmail%20for%20sme%20server.htm old HowTo] written for sme6.x.
{{Note box| Disregard all references to installing rpms as this does not apply to SME 7.x.
There are some small changes in database arrangement between the older SME 6.x db and the SME 7.x db.
There are some small changes in database arrangement between the older sme6.x db and the sme7.x db. Note also that there are many additional patterns in sme7.x. Note also that sme7.x uses qpsmtpd instead of smtpfront-qmail.
There are many additional patterns in SME 7.x. Note also that SME 7.x uses qpsmtpd instead of smtpfront-qmail.}}
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[[Category:Howto]]
[[Category:Howto]]
[[Category:Mail]]
[[Category:Mail]]
[[Category:Administration:Content Spam Virus Blocking]]
[[Category:Security]]
