Windows XP Hacks [Electronic resources] نسخه متنی

Hack 64 Open Blocked File Attachments in Outlook and Outlook Express

Force Outlook and Outlook Express to let you
open a wide variety of file attachments that they normally
block.

The
world is full of nasty email-borne worms and
viruses, and everyone certainly needs to be protected from them. But
Microsoft, in the latest versions of Outlook and Outlook Express,
takes a Big Nurse, draconian approach to the problem; it refuses to
let you open a wide variety of file attachments sent to you via
email, including those ending in .exe,
.bat, and many other common file extensions.
(Eudora doesn't!) The theory is that
there's a possibility that a file with one of those
extensions may be dangerous, so you shouldn't be
allowed to open any file with that extension.
That's like banning all cars because some people
sometimes get into accidents.

When you try to open a file with one of those blocked extensions, you
get the following error message: "Outlook blocked
access to the following potentially unsafe
attachments," and then you get a list of the
attachments in your email that you can't open.

Depending on your version of Outlook, Outlook Express and whether
you've applied a Service Pack update to either of
them, your version may or may not exhibit this behavior. Some older
versions don't act this way; all newer versions do.

The simplest way to know whether your version acts this way is to see
what happens when you get one of the blocked file attachments. If
it's allowed to go through, there's
no need to use this hack. If it's blocked, get thee
to the keyboard. Outlook and Outlook Express handle the problem
differently, so we'll take a look at each.

6.3.1 Force Outlook to Let You Open Blocked File Attachments

Outlook assigns a level of risk to
every file attachment sent to you. Level 1 is considered unsafe, so
Outlook blocks your access to them; you won't be
able to open the files. Level 2 is considered a moderate risk, and
you won't be able to open those files directly.
Instead, you have to save the files to disk, and then
you'll be able to open them. I'm
not clear on how that increases security, but that's
what Microsoft has done. Oh, and there's another
oddball fact about Level 2: no file types are considered Level 2
risks. The only way for a file to be considered at that risk level is
if you use Outlook in concert with a Microsoft Exchange Server and
the administrator uses his administration tools to put file
extensions into that risk category. The administrator is also the
only person who can take file extensions out of the category. So, you
can pretty much ignore that category, unless you have some convincing
official reason for changing your company's policy.
Any file types not in Levels 1 and 2 are considered
"other" and you can open them
normally.

To force Outlook to let you open
blocked file attachments, use this
Registry hack. Before
starting, you need to know the list of Level 1 file attachments that
Outlook blocks. They're listed in Table 6-2. Just to make things more confusing, depending
on your version of Office and what Service Pack
you've installed, not all of these extensions may be
blocked.

Decide which of the file extensions
you want to be able to open from within Outlook, and close down
Outlook if it's running. Then run the Registry
Editor [Hack #68] and go to
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security,
which, as its name implies, handles Outlook security. Create a new
String value called
Level1Remove. In the Value Data
field, type the name of the file extension that you want to be able
to openfor example, .exe. You can add
multiple file extensions. If you do, separate them with semicolons,
but no spaces, like this: .exe;.bat;.pif. Use
Table 6-2 as a guide for which blocked file
extensions you want to be able to open.

When you're done, exit the Registry and reboot.
You'll now be able to open the file extensions you
specified.

There's also an Outlook add-in that will let you
open blocked email attachments without having to edit the Registry.
The Attachment Options add-in, available
from
http://www.slovaktech.com/attachmentoptions,
lets you visually change which attachments you can open, and it also
lets you set an additional optionhaving Outlook ask you
whether you want to open certain file extensions on a case-by-case
basis, rather than blocking them or automatically opening them. The
author asks that you send a $10 donation if you use the add-in.

If you know who's sending you a certain attachment, you can also have them zip the file and resend it to you. That way, you're getting a file with a .zip file extension, which will get through.

6.3.2 Force Outlook Express to Let you Open Blocked File Attachments

Depending on your version of
Outlook Express,
it may prevent you from opening certain email file attachments, in
the same way that Outlook blocks certain files.

If you have installed Windows XP Service Pack 1, Outlook Express Service Pack 1, or Internet Explorer 6 Service Pack 1, you'll be blocked from opening certain email file attachments. Also, if you have a newer version of XP, you may also be blocked.

With Outlook Express, unlike with Outlook, you won't
be able to determine on an extension-by-extension basis which
attachments you can open. Instead, you can tell the program to let
you open all blocked extensions or you can tell it to stop you from
opening any blocked extensions.

To tell Outlook Express to let you open blocked attachments, choose
Tools Options Security and clear the box next
to "Do not allow attachments to be saved or opened
that could potentially be a virus," as shown in
Figure 6-6. You may have to close Outlook Express
and restart it in order for the settings to take effect.

Figure 6-6. Forcing Outlook Express to let you open all email attachments