Vulnerability Development mailing list archives

All systems with Internet Explorer IE 6.x /OPERA getting Files into your disk even if download is DISABLED Can be used also by BAD webs to fill your DISK


From: "Adonis.No.Spam" <adonis1 () videotron ca>
Date: Sat, 16 Mar 2002 07:50:55 -0500

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                          /    NtWaK0 Bugs  \
+-----------------------------------------------------------------------.
                                                                        :
Affected    : All systems with Internet Explorer IE 6.x /OPERA          :
Type        : getting Files into your disk even if download is          :
Type        : DISABLED. Can be used also by BAD webs to fill your DISK  :
Date        : 15-03-2002                                                :
Author      : NtWaK0 @ www.SafeHack.com                                 :
+-----------------------------------------------------------------------.

+---------------------.
 Device Identification \
+-----------------------`-----------------------------------------------.
                                                                        :
+-----------.                                                           :
 Disclaimer  \                                                          :
+-------------`---------------------------------------------------------.
The information in this advisory is believed to be true based on        :
experiments though it may be false. The opinions expressed in this      :
advisory and program are my own and NOT of any company.                 :
In Fact I do not work for no one at the present time.                   :
                                                                        :
This material is presented for informational and entertainment purposes :
only, and to satisfy the curious. Any activities described in this file :
which involve vandalism, theft, or any other illegal activities are     :
recounted from third-party conversations. I do not condone or encourage :
vandalism or theft. I do not accept any liability for anything anyone   :
does with this information.                                             :
Remember: Use a computer in ways that ensure respect for your fellows.  :
                                                                        :
+-------------.                                                         :
 Brief History \                                                        :
+---------------`-------------------------------------------------------.
This is not BIG issue but still something that need to be addressed.    :
                                                                        :
Internet Explorer 6.x allow you to save a file even if your security    :
Setting is HIGH (download file is disabled). Read below for more details:
                                                                        :
Opera will auto-download files with .cab extension as soon as you open  :
the html page.                                                          :
                                                                        :
Internet explorer and Opera are affected by this. Mozilla act PRETTY OK :
                                                                        :
+---------------------------+                                           :
Test OS Applications <<<                                           :
+---------------------------+                                           :
Tested on Windows 2k and XP                                             :
Tested on IE 6.x and opera                                              :
                                                                        :
+-----------.                                                           :
 The Problem \                                                          :
+-------------`---------------------------------------------------------.
If you are using IE 6.x (latest) you can still get files into your hard :
disk EVEN if IE security is HIGH which make download DISABLED.          :
                                                                        :
IE 6.x by default will save all .gif .cab .jpg etc,,, when you click    :
FROM THE MENU "SAVE AS".                                                :
This will save whatever .gif or .cab linked to the page.                :
                                                                        :
That can may FILL IN your hard disk if someone played some tricks with  :
the HTML page that you are saving.                                      :
To see the effect do this:                                              :
                                                                        :
1- Make sure to set your Internet Explorer Security To HIGH             :
   (this will disable download files) this mean your should not accept  :
   file into your hard disk.                                            :
2- From IE menu click "File" then "Save As".                            :
This will save this page to your disk and it will save whatever files I :
linked to this page. In this test page I linked 2 files in src tag.     :
You can see that if you check the source of this page.                  :
                                                                        :
TEST PAGE http://www.safehack.com/testpage/testsave.htm  <<<        :
                                                                        :
This page will save 2 files on your disk about 2.5 meg so be careful    :
if you are on slow link.                                                :
                                                                        :
Imaging someone put 20 hidden image in an HTML page that point to       :
src="test.cab" X 20 and every file let us say 100 Meg.                  :
When you save you wont save ONLY 100 MegX20 NO you will save 100 X 40   :
this because IE will have to get the file into a tmp folder first then  :
copy it to your disk.                                                   :
                                                                        :
Ah this can be used in another way too. How about you put one or two    :
src="test.cab" src="test1.gif"  on all your web pages and the src is    :
linked to a 500 MEG file, in this case NO ONE CAN SAVE YOUR PAGES unless:
they like to get the 500 meg file too. Sure this can be avoided if you  :
know how to save HTML using other method.                               :
                                                                        :
Opera will auto save the .cab file as soon as you open the HTML page.   :
Another problem with opera is even if you have a small cache size the   :
file will still get saved and renamed.                                  :
                                                                        :
To see that set your  opera cache size to one meg and re-open this page :
you will notice that opera did in fact save the file and renamed it.    :
                                                                        :
                                                                        :
+------------.                                                          :
 The Solution \                                                         :
+--------------`--------------------------------------------------------.
Before you save a page make sure you check the source. Yes it is not the:
best way but at least you know what you are expecting.                  :
+-----------------------------------------------------------------------.

________________________________________________________________________
The only secure computer is one that's unplugged, locked in a safe, 
and buried 20 feet under the ground in a secret location... and i'm 
not even too sure about that one"--Dennis Huges, FBI.
________________________________________________________________________
Connect yourself to the main computer and let me take you to a 
cybernetic ride. Are you connected to the right cybernet? If you are, 
finally you are connected to my brain.
________________________________________________________________________
-=- Use a computer in a ways that ensure respect for your fellow     -=-


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