Email, Spam Control, Attachment filters

On this page, you can learn the types of files that are not allowed as email attachments to or from @illinois.edu addresses

Introduction

As part of its efforts to protect the University of Illinois from malware and other email threats, Technology Services at Illinois blocks certain types of files from being sent or received as email attachments.
 
Tech Services does not expect that this or any one single solution will solve all problems associated with email security. But filtering these file types, combined with other steps, should help reduce the spread of phishing emails and malware on campus.
 

Q: How can I tell if an attachment has been filtered?

  1. If you receive and email, from outside the University mail system, then the email will have the subject line appended to show that the attachment was removed. 
  2. If you receive and email, from inside the University mail system, then the email will have a warning that says "Outlook blocked access to the following potentially unsafe attachment:{name}"

Q: I need to send or receive a file that is being filtered. What can I do?

The best way to send files is not through email attachments, but through Cloud-based supported file sharing services.
 

Q: Which file types are being filtered?

Previously, Tech Services Spam Control focused on blocking attachments that it had scanned and determined were malware. Now, in addition to scanning for and deleting malware sent by email, particular file types sent as email attachments will be removed from the emails
  • These file types are frequently used to try and deliver malware to campus through email. 
Tech Services does not expect these blocks to directly impact most email users as common formats of documents, spreadsheets, PDFs, and graphic files will not be filtered. 
  • However, if these files have embedded macros then they will be removed.
  • Please note that archive file types (.zip, .rar, .tar, etc.) will only be automatically filtered if they ARE encrypted or password protected. This is because if the archive uses a password or encryptions, we cannot tell if the archive contains malware. 
  • If the file is not encrypted, it will still be scanned for malware and blocked only if malware is detected.

 Archive files that are NOT password protected, NOT encrypted, and do NOT contain malware, can be sent and received normally.  


These executable file types are removed from email sent or received by @illinois.edu email accounts.

.386

.3gr

.ace

.add

.ade

.adp

.adt

.app

.arj

.asd

.asp

.aspx

.bas

.bat

.bin

.btm

.cbt

.ceo

.cer

.chm

.cla

.cmd

.cnt

.com

.cpl

.crt

.csc

.csh

.css

.dbx

.der

.dll

.docm

.drv

.email

.exe

.fon

.fxp

.gadget

.grp

.hlp

.hpj

.hta

.htr

.inf

.ins

.isp

.its

.jar

.je

.js

.jse

.ksh

.lib

.lnk

 .mad

.maf

.mag

.mam

.maq

.mar

.mas

.mat

.mau

.mav

.maw

.mcf

.mda

.mdb

.mde

.mdt

.mdw

.mdz

.mht

.msc

.msh

.msh1

.msh1xml

.msh2

.msh2xml

.mshxml

.msi

.mso

.msp

.mst

.obj

.ocx

.ops

.osd

.ov

.pcd

.pgm

.pif

.pl

.plg

.prc

.prf

.prg

.ps1

.py

.ps1xml

.ps2

.ps2xml

.psc1

.psc2

.pst

.reg

.scf

.scr

.sct

.shb

.shs

.smm

.swf

.sys

.tmp

.url

.vb

.vbe

.vbp

.vbs

.vsmacros

.vsw

.vxd

.ws

.wsc

.wsf

.wsh

.xbap

.xnk


These archive files types are allowed as long as they can be scanned. 

  • If the archive is encrypted, password protected or contains malware, then the file will be removed from the email.

.arc

.bz2

.cab

.gzip

.lha

.lzh

.rar

.ta

 .zip

.zipx

.zoo


Questions



Keywords:
Email spam control strip strips filter remove attachment file type prohibit prohibited block .exe blocked attachment 
Doc ID:
51416
Owned by:
Email Relays E. in University of Illinois Technology Services
Created:
2015-05-14
Updated:
2024-09-24
Sites:
University of Illinois Technology Services