If you use postfix and / or amavisd-new on the mail server, you can use the following recipes to block emails with executable (exe, bat, scr) attachments.
Block the attachments with a postfix header filter
In ISPConfig, click on "Email in the upper menu, then on "Content filter" in the left menu and click on the "Add new content filter" button. Enter the following details:
Filter:
MIME-Header Filter
Regexp. Pattern:
/^Content-(Disposition|Type).*name\s*=\s*"?(.*\.(bat|exe|scr))(\?=)?"?\s*(;|$)/x
Data:
File extension is blacklisted on this server
Action:
DISCARD
Use amavisd-new to block the emails with executable attachments.
Edit the amavisd configuration file (/etc/amavisd.conf or /etc/amavisd/amavisd.conf)
vi /etc/amavisd/amavisd.conf
and add the following lines:
$banned_filename_re = new_RE(
qr'.\.(bat|exe|scr)$'i,
qr'^\.(exe|zip|lha|tnef)$'i,
);
then restart amavisd-new:
/etc/init.d/amavis restart
.com files should be blocked too.
How do you block and send an email only to the recipient? and forward the block email to a specific address like remove@mydomain.com.
Hi, Is it really a file type blocking or only a file extension one?
I mean in both postfix and amavis-new…
Thanks
i tried to block *.zip, *bat and *.exe using this:
/^Content-(Disposition|Type).*name\s*=\s*”?(.*\.(zip|bat|exe))(\?=)?”?\s*(;|$)/x
but it’s not working as clients still can receive attached zip files.
the same. mime header filter not work