File extensions you can block in your email system

Generally, files attached to emails should be avoided for several reasons:

• Emails get heavier and some systems have size limitations
• You lose access to what is attached (with some exceptions, of course)
• Some systems might block specific extensions, and this is exactly what I am talking about

But, since we cannot prevent people from sending us emails with files attached, let’s at least block some file attachments that, if opened without a minimum check, and if sent by a malicious party, it could bring some devastating consequences in our infrastructure.

So here is the list:

ade
adp
app
asp
aspx
asx
bas
bat
cer
chm
cmd
cnt
com
cpl
crt
csh
der
diagcab
exe
fxp
gadget
grp
hlp
hpj
hta
htc
inf
ins
isp
its
jar
jnlp
js
jse
ksh
lnk
mad
maf
mag
mam
maq
mar
mas
mat
mau
mav
maw
mcf
mda
mdb
mde
mdt
mdw
mdz
msc
msh
msh1
msh2
mshxml
msh1xml
msh2xml
msi
msp
mst
msu
ops
osd
pcd
pif
pl
plg
prf
prg
printerexport
ps1
ps1xml
ps2
ps2xml
psc1
psc2
psd1
psdm1
pst
py
pyc
pyo
pyw
pyz
pyzw
reg
scf
scr
sct
shb
shs
theme
tmp
url
vb
vbe
vbp
vbs
vhd
vhdx
vsmacros
vsw
webpnp
website
ws
wsc
wsf
wsh
xbap
xll
xnk
appinstaller
application
appx
appxbundle
diagcab
diagpkg
diagcfg
fluid
fxb
glb
gltf
library-ms
loop
msix
partial
perfmoncfg
pko
ply
ppkg
qds
rat
resmoncfg
search-ms
searchConnector-ms
settingcontent-ms
stl
symlink
theme
themepack
UDL
url
wab
wbcat
wcx
website
whiteboard
xbap

You will find the CSV file here below

Feel free to share the ones you think are missing. I mainly used the ones recommended by Microsoft and some others I added.

P.S.: yes, I know it has been more than a year since my last post. Hopefully, you will not have to wait for another year to get another one 🙂