Office 2007 Bible

Dealing with Attachments

One of the most common ways for viruses to spread is by means of e-mail attachments. However, all attachments are not equal in their ability to spread a virus. Certain file types are potentially very dangerous, such as executable programs, batch files, and installation files. Others, such as image and music files, are generally safe.

Automatically blocked attachments

Because of the potential danger posed by some file types, Outlook blocks certain kinds of attachments that are sent to you; you receive the message with a notification that an unsafe attachment has been blocked. This blocking is built into Outlook and cannot be turned off or changed. The blocked file types are listed in Table 28-1.

Table 28-1. File Types That Are Blocked by Outlook

Extension	File Type
ADE	Access Project Extension (Microsoft)
ADP	Access project (Microsoft)
APP	Executable application
ASP	Active Server Page
BAS	BASIC source code
BAT	Batch processing
CER	Internet Security Certificate file
CHM	Compiled HTML jelp
CMD	DOS CP/M command file, or a command file for Windows NT
COM	Command
CPL	Windows Control Panel Extension (Microsoft)
CRT	Certificate file
CSH	csh script
DER	DER-encoded X509 certificate file
EXE	Executable file
FXP	FoxPro compiled source (Microsoft)
HLP	Windows Help file
HTA	Hypertext application
INF	Information or Setup file
INS	IIS Internet Communications settings (Microsoft)
ISP	IIS Internet Service Provider settings (Microsoft)
ITS	Internet Document Set, Internet Translation
JS	JavaScript source code
JSE	JScript ...