X-Git-Url: https://git.exim.org/exim-website.git/blobdiff_plain/51daf0470369914af68108f2dc4194f0fc5e4e73..4381ed22bb860a4f9dabd9c543814036a421d7b6:/system_filter.exim diff --git a/system_filter.exim b/system_filter.exim deleted file mode 100644 index 8dc8bb1..0000000 --- a/system_filter.exim +++ /dev/null @@ -1,187 +0,0 @@ -# Exim filter -## Version: 0.10 -# $Id$ - -## If you haven't worked with exim filters before, read -## the install notes at the end of this file. - -# -# Only run any of this stuff on the first pass through the -# filter - this is an optomisation for messages that get -# queued and have several delivery attempts -# -# we express this in reverse so we can just bail out -# on inappropriate messages -# -if not first_delivery -then - finish -endif - -# Check for MS buffer overruns as per latest BUGTRAQ. -# http://www.securityfocus.com/frames/?content=/templates/article.html%3Fid%3D61 -# This could happen in error messages, hence its placing -# here... -# We substract the first n characters of the date header -# and test if its the same as the date header... which -# is a lousy way of checking if the date is longer than -# n chars long -if ${length_80:$header_date:} is not $header_date: -then - fail text "This message has been rejected because it has\n\ - \tan overlength date field which can be used\n\ - \tto subvert Microsoft mail programs\n\ - \tThe following URL has further information\n\ - \thttp://www.securityfocus.com/frames/?content=/templates/article.html%3Fid%3D61" - seen finish -endif - -# 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 - 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 -# Check Content-Type header [vb2_regexp] -if $header_content-type: matches "(?:file)?name=(\"[^\"]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|bat|scr|pif)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|bat|scr|pif))" -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 -endif - -# 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|cmd|shs|bat|scr|pif)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|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 -endif - -#### Version history -# -# 0.01 5 May 2000 -# Initial release -# 0.02 8 May 2000 -# Widened list of content-types accepted, added WSF extension -# 0.03 8 May 2000 -# Embedded the install notes in for those that don't do manuals -# 0.04 9 May 2000 -# Check global content-type header. Efficiency mods to REs -# 0.05 9 May 2000 -# More minor efficiency mods, doc changes -# 0.06 20 June 2000 -# Added extension handling - thx to Douglas Gray Stephens & Jeff Carnahan -# 0.07 19 July 2000 -# 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 -# -#### Install Notes -# -# Exim filters run the exim filter language - a very primitive -# scripting language - in place of a user .forward file, or on -# a per system basis (on all messages passing through). -# The filtering capability is documented in the main set of manuals -# a copy of which can be found on the exim web site -# http://www.exim.org/ -# -# To install, copy the filter file (with appropriate permissions) -# to /etc/exim/system_filter.exim and add to your exim config file -# [location is installation depedant - typicaly /etc/exim/config ] -# at the top the line:- -# 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. -# -# After install exim should be restarted - a kill -HUP to the -# daemon will do this. -# -#### LIMITATIONS -# -# This filter tries to parse MIME with a regexp... that doesn't -# work too well. It will also only see the amount of the body -# specified in message_body_visible -# -#### BASIS -# -# The regexp that is used to pickup MIME/uuencoded parts is replicated -# below (in perl format). You need to remember that exim converts -# newlines to spaces in the message_body variable. -# -# (?:Content- # start of content header -# (?:Type: (?>\s*) # rest of c/t header -# [\w-]+/[\w-]+ # content-type (any) -# |Disposition: (?>\s*) # content-disposition hdr -# attachment) # content-disposition -# ;(?>\s*) # ; space or newline -# (?:file)?name= # filename=/name= -# |begin (?>\s+) [0-7]{3,4} (?>\s+)) # begin octal-mode -# (\"[^\"]+\. # quoted filename. -# (?:vb[se] # list of extns -# |ws[fh] -# |jse? -# |exe -# |com -# |cmd -# |shs -# |bat -# |scr -# |pif) -# \" # end quote -# |[\w.-]+\. # unquoted filename.ext -# (?:vb[se] # list of extns -# |ws[fh] -# |jse? -# |exe -# |com -# |cmd -# |shs -# |bat -# |scr -# |pif) -# ) # end of filename capture -# [\s;] # trailing ;/space/newline -# -# -### [End]