In Amavis banned attachments are controlled by the $banned_filename_re option in the Amavis config file.
Centos/RHEL/CLoudLinux/AlmaLinux
Edit the file /etc/amavisd.conf/amavisd.conf and search for the $banned_filename_re option. You can comment out or add new file extensions:
$banned_filename_re = new_RE(
### BLOCKED ANYWHERE
# qr'^UNDECIPHERABLE$', # is or contains any undecipherable components
qr'^\.(exe-ms|dll)$', # banned file(1) types, rudimentary
# qr'^\.(exe|lha|cab|dll)$', # banned file(1) types
### BLOCK THE FOLLOWING, EXCEPT WITHIN UNIX ARCHIVES:
# [ qr'^\.(gz|bz2)$' => 0 ], # allow any in gzip or bzip2
[ qr'^\.(rpm|cpio|tar)$' => 0 ], # allow any in Unix-type archives
qr'.\.(pif|scr)$'i, # banned extensions - rudimentary
# qr'^\.zip$', # block zip type
### BLOCK THE FOLLOWING, EXCEPT WITHIN ARCHIVES:
# [ qr'^\.(zip|rar|arc|arj|zoo)$'=> 0 ], # allow any within these archives
qr'^application/x-msdownload$'i, # block these MIME types
qr'^application/x-msdos-program$'i,
qr'^application/hta$'i,
# qr'^message/partial$'i, # rfc2046 MIME type
# qr'^message/external-body$'i, # rfc2046 MIME type
# qr'^(application/x-msmetafile|image/x-wmf)$'i, # Windows Metafile MIME type
# qr'^\.wmf$', # Windows Metafile file(1) type
# block certain double extensions in filenames
qr'^(?!cid:).*\.[^./]*[A-Za-z][^./]*\.\s*(exe|vbs|pif|scr|bat|cmd|com|cpl|dll)[.\s]*$'i,
# qr'\{[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}\}?'i, # Class ID CLSID, strict
# qr'\{[0-9a-z]{4,}(-[0-9a-z]{4,}){0,7}\}?'i, # Class ID extension CLSID, loose
qr'.\.(exe|vbs|pif|scr|cpl)$'i, # banned extension - basic
# qr'.\.(exe|vbs|pif|scr|cpl|bat|cmd|com)$'i, # banned extension - basic+cmd
# qr'.\.(ade|adp|app|bas|bat|chm|cmd|com|cpl|crt|emf|exe|fxp|grp|hlp|hta|
# inf|ini|ins|isp|js|jse|lib|lnk|mda|mdb|mde|mdt|mdw|mdz|msc|msi|
# msp|mst|ocx|ops|pcd|pif|prg|reg|scr|sct|shb|shs|sys|vb|vbe|vbs|vxd|
# wmf|wsc|wsf|wsh)$'ix, # banned extensions - long
# qr'.\.(asd|asf|asx|url|vcs|wmd|wmz)$'i, # consider also
# qr'.\.(ani|cur|ico)$'i, # banned cursors and icons filename
# qr'^\.ani$', # banned animated cursor file(1) type
# qr'.\.(mim|b64|bhx|hqx|xxe|uu|uue)$'i, # banned extension - WinZip vulnerab.
);
Debian/Ubuntu
Edit the file /etc/amavis/conf.d/20-debian_defaults and search for the $banned_filename_re option. You can comment out or add new file extensions:
$banned_filename_re = new_RE(
# qr'^UNDECIPHERABLE$', # is or contains any undecipherable components
# block certain double extensions anywhere in the base name
qr'\.[^./]*\.(exe|vbs|pif|scr|bat|cmd|com|cpl|dll)\.?$'i,
qr'\{[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}\}?$'i, # Windows Class ID CLSID, strict
qr'^application/x-msdownload$'i, # block these MIME types
qr'^application/x-msdos-program$'i,
qr'^application/hta$'i,
# qr'^application/x-msmetafile$'i, # Windows Metafile MIME type
# qr'^\.wmf$', # Windows Metafile file(1) type
# qr'^message/partial$'i, qr'^message/external-body$'i, # rfc2046 MIME types
# [ qr'^\.(Z|gz|bz2)$' => 0 ], # allow any in Unix-compressed
# [ qr'^\.(rpm|cpio|tar)$' => 0 ], # allow any in Unix-type archives
# [ qr'^\.(zip|rar|arc|arj|zoo)$'=> 0 ], # allow any within such archives
# [ qr'^application/x-zip-compressed$'i => 0], # allow any within such archives
qr'.\.(exe|vbs|pif|scr|bat|cmd|com|cpl)$'i, # banned extension - basic
# qr'.\.(ade|adp|app|bas|bat|chm|cmd|com|cpl|crt|emf|exe|fxp|grp|hlp|hta|
# inf|ins|isp|js|jse|lnk|mda|mdb|mde|mdw|mdt|mdz|msc|msi|msp|mst|
# ops|pcd|pif|prg|reg|scr|sct|shb|shs|vb|vbe|vbs|
# wmf|wsc|wsf|wsh)$'ix, # banned ext - long
# qr'.\.(mim|b64|bhx|hqx|xxe|uu|uue)$'i, # banned extension - WinZip vulnerab.
qr'^\.(exe-ms)$', # banned file(1) types
# qr'^\.(exe|lha|tnef|cab|dll)$', # banned file(1) types
);
Restart Amavis:
// Centos / RHEL / CloudLinux
systemctl restart amavisd
// Debian / Ubuntu
systemctl restart amavis