Exchange Online Protection Common Attachment Filter Update (Summer 2022)

Hi All,

As anounced the Microsoft common attachment filter has been updated with 53 default File Extensions and 219 File Extensions that can be selected. That’s a huge improvement to what was available end of last Year.

I want to remind you - it’s your responsability to define the Policy. Be aware that blocking *.bin Files can cause unintended affects

Blocking *.bin Files in EOP can cause block of Office Documents https://blog.icewolf.ch/archive/2022/08/01/blocking-bin-files-in-eop-can-cause-block-of-office.aspx

I’ve created a new Anti-Malware Policy via M365 Defender Portal https://security.microsoft.com/antimalwarev2

As you can see the Default Policy contains 53 File Extensions

Get-MalwareFilterPolicy -Identity Demo04 | select -ExpandProperty FileTypes | Measure
Get-MalwareFilterPolicy -Identity Demo04 | select -ExpandProperty FileTypes

These are the Default File Types:

ace
apk
app
appx
ani
arj
bat
cab
cmd
com
deb
dex
dll
docm
elf
exe
hta
img
iso
jar
jnlp
kext
lha
lib
library
lnk
lzh
macho
msc
msi
msix
msp
mst
pif
ppa
ppam
reg
rev
scf
scr
sct
sys
uif
vb
vbe
vbs
vxd
wsc
wsf
wsh
xll
xz
z

Get-MalwareFilterPolicy -Identity Demo05 | select -ExpandProperty FileTypes | measure

All Available File Extensions:

ace
apk
app
appx
ani
arj
bat
cab
cmd
com
deb
dex
dll
docm
elf
exe
hta
img
iso
jar
jnlp
kext
lha
lib
library
lnk
lzh
macho
msc
msi
msix
msp
mst
pif
ppa
ppam
reg
rev
scf
scr
sct
sys
uif
vb
vbe
vbs
vxd
wsc
wsf
wsh
xll
xz
z
ade
adp
asp
bas
cer
chm
cpl
crt
csh
der
dos
fxp
gadget
hlp
Hta
Inf
Ins
Isp
Its
js
Jse
Ksh
Lnk
mad
maf
mag
mam
maq
mar
mas
mat
mau
mav
maw
mda
mdb
mde
mdt
mdw
mdz
msh
msh1
msh1xml
msh2
msh2xml
mshxml
obj
ops
os2
pcd
plg
prf
prg
ps1
ps1xml
ps2
ps2xml
psc1
psc2
pst
rar
shb
shs
tmp
url
vsmacros
vsw
w16
ws
xnk
7z
7zip
a
accdb
accde
action
appxbundle
asf
aspx
avi
bin
bundle
bz
bz2
bzip2
caction
command
css
dgz
dmg
doc
docx
dot
dotm
dtox
dylib
font
gz
gzip
htm
html
imp
ipa
lqy
mht
mhtml
mscompress
msixbundle
o
odp
ods
odt
one
onenote
package
pages
pbix
pdb
pdf
php
pkg
plugin
pps
ppsm
ppsx
ppt
pptm
pptx
pub
py
rpm
rtf
scpt
service
sh
shtm
shx
so
tar
tarz
terminal
tgz
tool
vhd
vsd
vsdm
vsdx
vss
vssx
vst
vstm
vstx
workflow
xhtml
xla
xlam
xls
xlsb
xlsm
xlsx
xlt
xltm
xltx
zi
zip
zipx

Hope this helps.

Regards
Andres Bohren