AusCERT - ESB-2001.103 -- Microsoft Security Bulletin MS01-015 -- IE can Divulge Location of Cached Content

HOME
About AusCERT
Membership
PKI Services
Training
Publications
Sec. Bulletins
Conferences
News & Media
Services
Web Log
Site Map
Site Help
Member login
ESB-2001.103 -- Microsoft Security Bulletin MS01-015 -- IE can Divulge Location of Cached Content
Date: 07 March 2001
References: ESB-2000.101 ESB-2000.204 ESB-2000.386 ESB-2001.159

Click here for printable version
-----BEGIN PGP SIGNED MESSAGE-----

===========================================================================
             AUSCERT External Security Bulletin Redistribution

           ESB-2001.103 -- Microsoft Security Bulletin MS01-015
                 IE can Divulge Location of Cached Content
                               7 March 2001

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                Microsoft Internet Explorer 5.01
                        Microsoft Internet Explorer 5.5 
                        Microsoft Windows Scripting Host 5.1
                        Microsoft Windows Scripting Host 5.5
Vendor:                 Microsoft
Impact:                 Execute Arbitrary Code/Commands
                        Create Arbitrary Files
                        Read-only Data Access
Access Required:        Remote

Ref:                    ESB-2000.386
                        ESB-2000.204
                        ESB-2000.101

- --------------------------BEGIN INCLUDED TEXT--------------------

- -----BEGIN PGP SIGNED MESSAGE-----

- - ----------------------------------------------------------------------
Title:      IE can Divulge Location of Cached Content
Date:       06 March 2001
Software:   IE and Windows Scripting Host
Impact:     Run code of attacker's choice. Three other
            vulnerabilities, of lesser severity and exploitable in
            more restricted circumstances, also are eliminated by
            the patches.
Bulletin:   MS01-015

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-015.asp.
- - ----------------------------------------------------------------------

Issue:
======
The IE security architecture provides a caching mechanism that is
used to store content that  needs to be downloaded and processed on
the user's local machine. The purpose of the cache  is to obfuscate
the physical location of the cached content, in order to ensure that
the web  page or HTML e-mail will work through the IE security
architecture to access the  information. This ensures that the uses
of the information can be properly restricted.

A vulnerability exists because it is possible for a web page or HTML
e-mail to learn the  physical location of cached content. Armed with
this information, an attacker could cause  the cached content to be
opened in the Local Computer Zone. This would enable him to launch 
compiled HTML help (.CHM) files that contain shortcuts to
executables, thereby enabling him  to run the executables.

In addition to eliminating this vulnerability, the patches provided
below eliminate three  other vulnerabilities that either pose
significantly less risk or could only be exploited in  very
restricted situations: 
 - A variant of the "Frame Domain Verification" vulnerability 
   discussed in Microsoft Security Bulletins MS00-033, MS00-055,
   and MS00-093. The vulnerability could enable a malicious web
   site operator to open two browser windows, one in the web 
   site's domain and the other on the user's local file system,
   and to pass information from the latter to the former. This
   could enable the web site operator to read, but not change,
   any file on the user's local computer that could be opened
   in a browser window. 
 - A vulnerability that is identical in effect to the "Frame 
   Domain Verification" vulnerability, but which actually results
   from a flaw in Windows Scripting Host rather than IE. Because
   it could only be exploited via IE, we have provided the patch
   here. 
 - A vulnerability that affects how Telnet sessions are invoked
   via IE. By design, telnet sessions can be launched via IE. 
   However, a vulnerability exists because when doing so, IE will
   start Telnet using any command-line options the web site 
   specifies. This only becomes a concern when using the version
   of the Telnet client that installs as part of Services for 
   Unix (SFU) 2.0 on Windows NT(r) 4.0 or Windows(r) 2000 
   machines. The version of the Telnet client in SFU 2.0 provides
   an option for creating a verbatim transcript of a Telnet 
   session. An attacker could start a session using the logging
   option, then stream an executable file onto the user's system
   in a location that would cause it to be executed automatically
   the next time the user booted the machine. The flaw does not
   lie in the Telnet client, but in IE, which should not allow
   Telnet to be started remotely with command-line arguments. 

Mitigating Factors:
====================
 - None of the vulnerabilities could be exploited without some
   user action - either browsing to the attacker's site or opening
   a mail from him. Customers who exercise safe browsing habits
   would be less likely visit untrustworthy sites, and customers
   who have used the Security Zones feature to restrict what HTML
   mail can do would be less likely to be affected by this 
   vulnerability. 
 - The variants of the "frame domain verification" vulnerability 
   discussed above could only be used to view files, and only file
   types that can be opened in a browser window. 
 - The vulnerability affecting Telnet invocation is only a concern
   for customers who are using the Telnet client that ships as
   part of Services for Unix 2.0. Other versions of Telnet do not 
   include the command-line feature to create log files. 

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletin
   http://www.microsoft.com/technet/security/bulletin/ms01-015.asp
   for information on obtaining this patch.

- - ---------------------------------------------------------------------

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED
"AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY
DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO
THE FOREGOING LIMITATION MAY NOT APPLY.



- -----BEGIN PGP SIGNATURE-----
Version: PGP Personal Privacy 6.5.3

iQEVAwUBOqWGu40ZSRQxA/UrAQGe6Qf/aquL16DbXe0EzfM4YcyzIk8a8kUUL2iO
p7J2nHFntGFFz3j7rG0kDpR3CB9ET9TRauJK3oMikMPC1e6YCpe2jQbzUDVG+py/
TnpU3TmJeGDQmFj7ygbp+5BGaZNtaGbdsOBKjZevCtIx6hdPK2zvWEYHAvNpj0x1
u4HahwsvLfxbNMeqqNL0Wls/hbjK+ts01gDReSg/lzazLQ+sYLi4LD+9AbNgF+mE
/KIv873xbNTbWivHWQ8m6LnE93+xmEISQ7u1JrZkxAOjgb3CB6XVwjyih4CcjjxF
hI5IHoxfElOx4+KsCWjAQUuIixAUiEGmEDkhR5nRForBP5M0gN1f4w==
=9OOz
- -----END PGP SIGNATURE-----


- --------------------------END INCLUDED TEXT--------------------

This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content.  The decision to use any or all of this information is
the responsibility of each user or organisation, and should be done so in
accordance with site policies and procedures.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

	http://www.auscert.org.au/Information/advisories.html

If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security
Teams).

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.

-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key

iQCVAwUBOqZKDSh9+71yA2DNAQHZtAP9ENSjRXaLq/01S6K1/UJXt5H1ejayAvmW
qWxWAEuSNpW+CFMZa98DJXpEAS7vppmC8ayBoaiy/VlCVZzeRNDiskpn7pAuNfxU
lMC7yG2F3yZfh1ipMH8X2F3NeoTqygSZMUj/yxh/ZhV2CX8UiRAUCT8qvb75ysDO
+ujtn0wX9s4=
=uazx
-----END PGP SIGNATURE-----