Software Restriction Policy flaw

  • Thread starter Thread starter Jeremy Harrington
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Jeremy Harrington

I have deployed a Group Policy for a certain subset of users that only allows
them to use Internet Explorer. To do so, I set Software Restriction with a
default setting of "Deny," with the only exception being IE. With basic
testing, it seems to work perfectly.

However, if you perform the following steps from within IE, you can run any
application, in complete disregard for the GP.

1) Open IE
2) Go to File->Open
3) Click the "Browse" button
4) Change the "Files of Type" drop down to "All Files"
5) Browse to any app that shouldn't run.
6) Hold down CTRL-SHIFT while right clicking the app to bring up the "Run
As" option and click "Run As"
7) Leave the default options (current user with checked box) selected and
click "Ok"

I tried this with multiple applications, and it worked every time. The fact
that 99% of users will never try this is irrelevent. This makes software
restriction security by obscurity, rather than a tool to be counted on.
 
Jeremy said:
I have deployed a Group Policy for a certain subset of users that
only allows them to use Internet Explorer. To do so, I set Software
Restriction with a default setting of "Deny," with the only
exception being IE. With basic testing, it seems to work perfectly.

However, if you perform the following steps from within IE, you can
run any application, in complete disregard for the GP.

1) Open IE
2) Go to File->Open
3) Click the "Browse" button
4) Change the "Files of Type" drop down to "All Files"
5) Browse to any app that shouldn't run.
6) Hold down CTRL-SHIFT while right clicking the app to bring up
the "Run As" option and click "Run As"
7) Leave the default options (current user with checked box)
selected and click "Ok"

I tried this with multiple applications, and it worked every time.
The fact that 99% of users will never try this is irrelevent. This
makes software restriction security by obscurity, rather than a
tool to be counted on.
Click to expand...

Not new. Google on it?

June 2006 article:
http://www.derkeiler.com/Mailing-Lists/securityfocus/bugtraq/2006-06/msg00243.html

(Including a supposed response from Microsoft concerning the 'issue'...)
 
I didn't expect it to be new, I'm just hoping someone has come up with
something half-way intelligent as a fix since 2006 (when that particular post
was created).
 
Jeremy Harrington said:
I have deployed a Group Policy for a certain subset of users that only allows
them to use Internet Explorer.
Click to expand...

That is akin to saying that your kids are unruly, so you will only allow
them the use of the Carl Gustav. <G>

There are few programs which expose the computer to so great a security risk
as IE.
 
Try using these policies:
1. Within IE, disable the "File > Open" menu option.
2. Enable the "Allowed Windows Apps" policy, and populate that list with
applications that you wish to allow.
3. Prevent access to C: drive + disable file browsing so that they can't go
searching for the app.
4. Disable the Run-As option
 
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