> From: Raymond Jette
> I'm having some trouble setting my EXIM to filter attachments correctly.
> I would like to extract all attachments and then make sure they do not
> contain any binaries. If they do EXIM should reject the message.
> deny message = Attachment has unsupported file format inside zip file
> demime = zip
> egrep -I '[.](bat|btm|cmd|com|cpl|dat|dll|exe|lnk|msi|pif|prf|reg|scr|vb|vbs)$' | \
Try (untested):
acl_smtp_mime = acl_check_mime
begin acl
acl_check_mime:
deny message = A .zip attachment contains a Windows-executable file - \
blocked because we are afraid of new viruses \
not recognized [yet] by antiviruses.
condition = ${if match{$mime_filename}{\N(?i)\.zip$\N}}
condition = ${if def:sender_host_address}
condition = ${if !def:sender_host_authenticated}
decode = default
log_message = forbidden binary in attachment: filename=$mime_filename, \
recipients=$recipients
condition = ${if match{${run{/usr/local/bin/unzip -l \
$mime_decoded_filename}}}\
{\N(?i)\.(exe|com|vbs|bat|pif|scr|hta|js\
|cmd|chm|cpl|jsp|reg|vbe|lnk|dll|sys|btm|dat|msi|prf|vb)\n\N}}
deny message = Windows-executable attachments forbidden because we are \
afraid of new viruses not recognized [yet] by antiviruses.
condition = ${if def:sender_host_address}
condition = ${if !def:sender_host_authenticated}
log_message = forbidden attachment: filename=$mime_filename, \
content-type=$mime_content_type, recipients=$recipients
condition = ${if or{\
{match{$mime_content_type}{(?i)executable}}\
{match{$mime_filename}{\N(?i)\.(exe|com|vbs|bat|pif\
|scr|hta|js|cmd|chm|cpl|jsp|reg|vbe|lnk|dll|sys|btm|dat|msi|prf|vb)$\N}}\
}}
accept
