built filter from source

[exim-website.git] / system_filter.exim

diff --git a/system_filter.exim b/system_filter.exim
index 91f456e443f0764183915f5728dd3122ada96f81..f920ac8ca5a5143a1fd71cc9b43430124296ab1c 100644 (file)
--- a/system_filter.exim
+++ b/system_filter.exim
@@ -1,5 +1,6 @@
 # Exim filter
 # Exim filter

-## Version: 0.08
+## Version: 0.13
+#      $Id: system_filter.exim,v 1.3 2001/05/18 10:28:13 nigel Exp $

 
 ## If you haven't worked with exim filters before, read
 ## the install notes at the end of this file.
 
 ## If you haven't worked with exim filters before, read
 ## the install notes at the end of this file.


@@ -35,37 +36,68 @@ then
   seen finish
 endif
 
   seen finish
 endif
 

-# drop out error messages here
-if error_message
+# This is a nasty compromise.
+# This crud is now being sent with a <> envelope sender, but
+# blocking all error messages that pattern match prevents
+# bounces getting back.... so we fudge it somewhat
+if $header_from: contains "@sexyfun.net"

 then
 then

+  fail text "This message has been rejected since it has\n\
+               \tthe signature of a known virus in the header."
+  seen finish
+endif
+if error_message and $header_from: contains "Mailer-Daemon@"
+then
+  # looks like a real error message - just ignore it

   finish
 endif
 
 # Look for single part MIME messages with suspicious name extensions
   finish
 endif
 
 # Look for single part MIME messages with suspicious name extensions

-# Check Content-Type header [vb2_regexp]
-if $header_content-type: matches "(?:file)?name=(\"[^\"]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|shs|bat)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|shs|bat))"
+# Check Content-Type header using quoted filename [content_type_quoted_fn_match]
+if $header_content-type: matches "(?:file)?name=(\"[^\"]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif)\")"
+then
+  fail text "This message has been rejected because it has\n\
+            \tpotentially executable content $1\n\
+            \tThis form of attachment has been used by\n\
+             \trecent viruses or other malware.\n\
+            \tIf you meant to send this file then please\n\
+            \tpackage it up as a zip file and resend it."
+  seen finish
+endif
+# same again using unquoted filename [content_type_unquoted_fn_match]
+if $header_content-type: matches "(?:file)?name=([\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif))"

 then
   fail text "This message has been rejected because it has\n\
 then
   fail text "This message has been rejected because it has\n\

-            \tan apparently executable attachment $1\n\
+            \tpotentially executable content $1\n\

             \tThis form of attachment has been used by\n\
             \tThis form of attachment has been used by\n\

-             \trecent viruses such as that described in\n\
-            \thttp://www.fsecure.com/v-descs/love.htm\n\
+             \trecent viruses or other malware.\n\

             \tIf you meant to send this file then please\n\
             \tpackage it up as a zip file and resend it."
   seen finish
 endif
 
             \tIf you meant to send this file then please\n\
             \tpackage it up as a zip file and resend it."
   seen finish
 endif
 

+

 # Attempt to catch embedded VBS attachments
 # in emails.   These were used as the basis for 
 # the ILOVEYOU virus and its variants
 # Attempt to catch embedded VBS attachments
 # in emails.   These were used as the basis for 
 # the ILOVEYOU virus and its variants

-# [vb_regexp]
-if $message_body matches "(?:Content-(?:Type:(?>\\\\s*)[\\\\w-]+/[\\\\w-]+|Disposition:(?>\\\\s*)attachment);(?>\\\\s*)(?:file)?name=|begin(?>\\\\s+)[0-7]{3,4}(?>\\\\s+))(\"[^\"]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|shs|bat)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|shs|bat))[\\\\s;]"
+# Quoted filename - [body_quoted_fn_match]
+if $message_body matches "(?:Content-(?:Type:(?>\\\\s*)[\\\\w-]+/[\\\\w-]+|Disposition:(?>\\\\s*)attachment);(?>\\\\s*)(?:file)?name=|begin(?>\\\\s+)[0-7]{3,4}(?>\\\\s+))(\"[^\"]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif)\")[\\\\s;]"

 then
   fail text "This message has been rejected because it has\n\
 then
   fail text "This message has been rejected because it has\n\

-            \tan apparently executable attachment $1\n\
+            \ta potentially executable attachment $1\n\

             \tThis form of attachment has been used by\n\
             \tThis form of attachment has been used by\n\

-             \trecent viruses such as that described in\n\
-            \thttp://www.fsecure.com/v-descs/love.htm\n\
+             \trecent viruses or other malware.\n\
+            \tIf you meant to send this file then please\n\
+            \tpackage it up as a zip file and resend it."
+  seen finish
+endif
+# same again using unquoted filename [body_unquoted_fn_match]
+if $message_body matches "(?:Content-(?:Type:(?>\\\\s*)[\\\\w-]+/[\\\\w-]+|Disposition:(?>\\\\s*)attachment);(?>\\\\s*)(?:file)?name=|begin(?>\\\\s+)[0-7]{3,4}(?>\\\\s+))([\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif))[\\\\s;]"
+then
+  fail text "This message has been rejected because it has\n\
+            \ta potentially executable attachment $1\n\
+            \tThis form of attachment has been used by\n\
+             \trecent viruses or other malware.\n\

             \tIf you meant to send this file then please\n\
             \tpackage it up as a zip file and resend it."
   seen finish
             \tIf you meant to send this file then please\n\
             \tpackage it up as a zip file and resend it."
   seen finish


@@ -89,6 +121,22 @@ endif
 #      Latest MS Outhouse bug catching
 # 0.08 19 July 2000
 #      Changed trigger length to 80 chars, fixed some spelling
 #      Latest MS Outhouse bug catching
 # 0.08 19 July 2000
 #      Changed trigger length to 80 chars, fixed some spelling

+# 0.09 29 September 2000
+#      More extensions... its getting so we should just allow 2 or 3 through
+# 0.10 18 January 2001
+#      Removed exclusion for error messages - this is a little nasty
+#      since it has other side effects, hence we do still exclude
+#      on unix like error messages
+# 0.11 20 March, 2001
+#      Added CMD extension, tidied docs slightly, added RCS tag
+#      ** Missed changing version number at top of file :-(
+# 0.12 10 May, 2001
+#      Added HTA extension
+# 0.13 22 May, 2001
+#      Reformatted regexps and code to build them so that they are
+#      shorter than the limits on pre exim 3.20 filters.  This will
+#      make them significantly less efficient, but I am getting so
+#      many queries about this that requiring 3.2x appears unsupportable.

 #
 #### Install Notes
 #
 #
 #### Install Notes
 #


@@ -106,6 +154,13 @@ endif
 #      message_filter = /etc/exim/system_filter.exim
 #      message_body_visible = 5000
 #
 #      message_filter = /etc/exim/system_filter.exim
 #      message_body_visible = 5000
 #

+# You may also want to set the message_filter_user & message_filter_group
+# options, but they default to the standard exim user and so can
+# be left untouched.  The other message_filter_* options are only
+# needed if you modify this to do other functions such as deliveries.
+# The main exim documentation is quite thorough and so I see no need
+# to expand it here...
+#

 # Any message that matches the filter will then be bounced.
 # If you wish you can change the error message by editing it
 # in the section above - however be careful you don't break it.
 # Any message that matches the filter will then be bounced.
 # If you wish you can change the error message by editing it
 # in the section above - however be careful you don't break it.


@@ -139,8 +194,12 @@ endif
 #      |jse?
 #      |exe
 #      |com
 #      |jse?
 #      |exe
 #      |com

+#      |cmd

 #      |shs
 #      |shs

-#      |bat)
+#      |hta
+#      |bat
+#      |scr
+#      |pif)

 #      \"                                      # end quote
 #  |[\w.-]+\.                                  # unquoted filename.ext
 #      (?:vb[se]                               # list of extns
 #      \"                                      # end quote
 #  |[\w.-]+\.                                  # unquoted filename.ext
 #      (?:vb[se]                               # list of extns


@@ -148,10 +207,14 @@ endif
 #      |jse?
 #      |exe
 #      |com
 #      |jse?
 #      |exe
 #      |com

+#      |cmd

 #      |shs
 #      |shs

-#      |bat)
+#      |hta
+#      |bat
+#      |scr
+#      |pif)

 #  )                                           # end of filename capture
 #  )                                           # end of filename capture

-#  [\s;]                                               # trailing ;/space/newline
+#  [\s;]                                       # trailing ;/space/newline

 #
 #
 ### [End]
 #
 #
 ### [End]