# Exim filter
## Version: 0.12
-# $Id: system_filter.exim,v 1.4 2001/03/20 21:24:40 nigel Exp $
+# $Id: system_filter.exim,v 1.2 2001/05/10 11:35:45 nigel Exp $
## If you haven't worked with exim filters before, read
## the install notes at the end of this file.
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|hta|bat|scr|pif)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif))"
+# 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\
- \ta potentially executable attachment $1\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\
+ \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\
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|hta|bat|scr|pif)\"|[\\\\w.-]+\\\\.(?:vb[se]|ws[fh]|jse?|exe|com|cmd|shs|hta|bat|scr|pif))[\\\\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\
+ \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
+# 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\