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Blocked Attachments on Exchange

One of the ways that KU protects Exchange users from malicious software is by blocking attachments that may be used to transmit viruses or malicious software.

The table below contains a description of file types currently being blocked along with the common file extensions for these files.

See FAQ section below for more details.

Description Extension
MS Access Project Extension ade
MS Access Project adp
Archive file (See FAQ, below) arc
Visual Basic Class Module bas
batch file bat
Archive file (See FAQ, below) cab
Compiled HTML Help file chm
Java Class File cla / class
Windows NT command script cmd
MS-DOS application com
Control panel extension cpl
Security certificate crt
Application exe
Archive file (See FAQ, below) gzip
Windows Help file hlp
HTML applications hta
Setup information file inf
Internet communication settings ins
Internet communication settings isp
Archive file (See FAQ, below) jar
Jscript file js
Jscript encoded script file jse
Java Server Page jsp
MS common console document msc
Windows Installer file msi / mst
OLE Control Extension ocx
Kodak Photo CD Multiresolution Image pcd
Shortcut to MS-DOS programs pif
Archive file (See FAQ, below) rar
Registration entries reg
Screen saver scr
Windows script component sct
shell scrap object shs
Archive file (See FAQ, below) sit
Archive file (See FAQ, below) tar
Archive file (See FAQ, below) tgz
VBscript file vb
VBscript encoded script file vbe
VBscript script file vbs
Archive file (See FAQ, below) war
Windows script component wsc
Windows script file wsf
Windows scripting host settings file wsh
Archive file (See FAQ, below) zip

FAQ:

How do I know a file is being blocked?

The KU Exchange user that is sending or receiving a blocked attachment receives an email notification that an attachment has been blocked.

A file is being blocked. What do I do?

Renaming the file extension won't work. The scanning software is smart enough to detect the blocked filetypes, even if they're renamed.

To send or receive an attachment that is being blocked, the sender of the message must first place the file into a password-protected archive file, then attach it to the message. There are a variety of Windows and Macintosh programs that can create these files, including WinZip and StuffIt.

The sender should include instructions in the email telling the recipient the archive type and contents. The password can be transmitted in the email message or by phoning the recipient.

Password-protected archives should NEVER be used to transmit any data that is confidential or protected, because password-protected archives are easy to decode by any determined hacker.

Why is my archive file being blocked?

Archive files are NOT automatically blocked. The only time an archive file is not delivered is when it contains a file that is of a type that is blocked.

If an archive file is blocked, the sender needs to put the archive file into a password protected archive file (yes, an archive within an archive), then send that file to the recipient.

The sender should include instructions in the email telling the recipient the archive type and contents. The password can be transmitted in the email message or by phoning the recipient.

Password-protected archives should NEVER be used to transmit any data that is confidential or protected, because password-protected archives are easy to decode by any determined hacker.