Unsafe File Types

Microsoft has deemed email attachments with certain extensions to be unsafe. The SSU email server filters unsafe attachments from messages, and a notice that the attachment has been removed is inserted in the message.

SSU email users have seen an increasing number of viruses that use email to spread. This problem is not expected to diminish in the near future.

If you need to send a file attachment with one of these extensions, you can rename the file so that it no longer has the original extension. In the message body you can include instructions for renaming the file back to its original name.

General Advice on File Attachments in Email Messages

  • If you receive a message with one of these unsafe attachments, don’t open the attachment. Delete the attachment.
  • If you receive any file attachment from someone you don’t know or if you know the person but are not expecting a file, don’t open the attachment.

Microsoft classifies the following extensions as unsafe.

Possible Unsafe Extensions

.ade
Microsoft Access project extension
.adp
Microsoft Access project
.bas
Microsoft Visual Basic class module
.bat
Batch file
.chm
Compiled HTML Help file
.cmd
Microsoft Windows NT Command script
.com
Microsoft MS-DOS program
.cpl
Control Panel extension
.crt
Security certificate
.exe
Program
.hlp
Help file
.hta
HTML program
.inf
Setup Information
.ins
Internet Naming Service
.isp
Internet Communication settings
.js
JScript file
.jse
Jscript Encoded Script file
.lnk
Shortcut
.mdb
Microsoft Access program
.mde
Microsoft Access MDE database
.msc
Microsoft Common Console document
.msi
Microsoft Windows Installer package
.msp
Microsoft Windows Installer patch
.mst
Microsoft Visual Test source files
.pcd
Photo CD image, Microsoft Visual compiled script
.pif
Shortcut to MS-DOS program
.reg
Registration entries
.scr
Screen saver
.sct
Windows Script Component
.shb
Shell Scrap object
.shs
Shell Scrap object
.url
Internet shortcut
.vb
VBScript file
.vbe
VBScript Encoded script file
.vbs
VBScript file
.wsc
Windows Script Component
.wsf
Windows Script file
.wsh
Windows Script Host Settings file