-----Original Message-----
From: UNIRAS (UK Govt CERT)
Sent: 13 December 2002 10:19
To: [EMAIL PROTECTED]
Subject: UNIRAS Brief - 444/02 - Microsoft - Flaw in Microsoft VM Could
Enable System Compromise
-----BEGIN PGP SIGNED MESSAGE-----
-
------------------------------------------------------------------------
----------
UNIRAS (UK Govt CERT) Briefing Notice - 444/02 dated 13.12.02 Time:
10.20
UNIRAS is part of NISCC(National Infrastructure Security Co-ordination
Centre)
-
------------------------------------------------------------------------
----------
UNIRAS material is also available from its website at
www.uniras.gov.uk and
Information about NISCC is available from www.niscc.gov.uk
-
------------------------------------------------------------------------
----------
Title
=====
Microsoft Security Bulletin - MS02-069:
Flaw in Microsoft VM Could Enable System Compromise
Detail
======
- -----BEGIN PGP SIGNED MESSAGE-----
- -
----------------------------------------------------------------------
Title: Flaw in Microsoft VM Could Enable System
Compromise (810030)
Date: 11 December 2002
Software: Microsoft VM
Impact: Eight vulnerabilities, the most serious of which
would enable an attacker to gain control over
another user's system.
Max Risk: Critical
Bulletin: MS02-069
Microsoft encourages customers to review the Security Bulletins at:
http://www.microsoft.com/technet/security/bulletin/MS02-069.asp
http://www.microsoft.com/security/security_bulletins/ms02-069.asp.
- -
----------------------------------------------------------------------
Issue:
======
The Microsoft VM is a virtual machine for the Win32(r) operating
environment. The Microsoft
VM shipped in most versions of Windows (a complete list is available
in the FAQ), as well as
in most versions of Internet Explorer.
A new version of the Microsoft VM is available, which includes all
previously released fixes
for the VM, as well as fixes for eight newly reported security
issues. The attack vectors
for all of the new issues would likely be the same. An attacker would
create a web page
that, when opened, exploits the desired vulnerability, and either
host it on a web page or
send it to a user as an HTML mail.
The newly reported security issues are as follows:
- A security vulnerability through which an untrusted
Java applet could access COM objects. By design, COM
objects should only be available to trusted Java
programs because of the functionality they expose. COM
objects are available that provide functionality through
which an attacker could take control of the system.
- A pair of vulnerabilities that, although having
different underlying causes, would have the same effect,
namely, disguising the actual location of the applet's
codebase. By design, a Java applet that resides on user
storage or a network share has read access to the folder
it resides in and all folders below it. The
vulnerabilities provide methods by which an applet
located on a web site could misrepresent the location of
its codebase, to indicate that it resided instead on the
user's local system or a network share.
- A vulnerability that could enable an attacker to construct
an URL that, when parsed, would load a Java applet from
one web site but misrepresent it as belonging to another
web site. The result would be that the attacker's applet
would run in the other site's domain. Any information the
user provided to it could be relayed back to the attacker.
- A vulnerability that results because the Microsoft VM
doesn't prevent applets from calling the JDBC APIs - a
set of APIs that provide database access methods. By
design, these APIs provide functionality to add, change,
delete or modify database contents, subject only to the
user's permissions.
- A vulnerability through which an attacker could
temporarily prevent specified Java objects from being
loaded and run. A legacy security mechanism known as the
Standard Security Manager provides the ability to impose
restrictions on Java applets, up to and including
preventing them from running altogether. However, the VM
does not adequately regulate access to the SSM, with the
result that an attacker's applet could add other Java
objects to the "banned" list.
- A vulnerability through which an attacker could learn a
user's username on their local system. The vulnerability
results because one particular system property, user.dir,
should not be available to untrusted applets but, through
a flaw, is. While knowing a username would not in itself
pose a security risk, it could be useful for
reconnaissance purposes.
- A vulnerability that results because it's possible for a
Java applet to perform an incomplete instantiation of
another Java object. The effect of doing so would be to
cause the containing application - Internet Explorer - to
fail.
Mitigating Factors:
====================
All of the vulnerabilities share a pair of common mitigating factors:
- The web-based attack vector would be blocked if the user
had disabled Java applets in the Internet Explorer
security zone in which the attacker's web site rendered.
- The email vector would be blocked if the user were running
any of several mail clients. Specifically, Outlook
Express 6 and Outlook 2002 (which ships as part of Office
XP) disable Java by default, and Outlook 98 and 2000
disable it if the Outlook Email Security Update has been
installed.
COM Object Access Vulnerability:
- The vulnerability represents a target of opportunity only.
The attacker would have no means of ensuring that
sensitive data would be located in system memory, cookies,
the clipboard, or other locations.
CODEBASE Spoofing Vulnerabilities:
- The attacker's access to files, including those on remote
shares, would be limited to those of the user. If the
user had only limited permissions, so would the attacker.
Domain Spoofing Vulnerability:
- The vulnerability could only be exploited if the user
visited the attacker's site en route to visiting a
third-party site.
- The effect of exploiting the vulnerability would apply
only to the current web session.
JDBC API Vulnerability:
- To exploit this vulnerability, the attacker would need
to know the names of each data source he or she wanted
to access. In most cases, this would require the attacker
to have insider knowledge of the user's network.
- The attacker would gain only the user's own permissions
to the data sources. For instance, if the user had only
read access to a particular database, so would the
attacker.
Standard Security Manager Access Vulnerability:
- The effect of exploiting this vulnerability would only
persist during the current browser session.
- The vulnerability provides no means of modifying an
applet's functioning - only preventing it from running.
User.dir Exposure Vulnerability:
- Knowing a user's username would not, by itself, enable
an attacker to take any action against the user. The
sole value in learning this information would be for
reconnaissance purposes, in the hope of using it in
some future, unspecified attack.
Incomplete Java object Instantiation Vulnerability:
- This vulnerability would only enable the attacker to
cause Internet Explorer to fail - it would not enable
the attacker to cause Windows itself, or any other
applications, to fail.
- The user could restore normal operation by restarting
the browser.
Risk Rating:
============
- COM Object Access Vulnerability: Critical
- CODEBASE Spoofing Vulnerabilities: Important
- Domain Spoofing Vulnerability: Moderate
- JDBC API Vulnerability: Moderate
- Standard Security Manager Access Vulnerability: Low
- User.dir Exposure Vulnerability: Low
- Incomplete Java object Instantiation Vulnerability: Low
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-069.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 7.1
iQEVAwUBPfe8II0ZSRQxA/UrAQE+wAf/WdruD788OEm/Gg3SAhJv9VLRfQ7ck+3F
Q6e6hh21UmJmGXMtlsUzNyccvK0fELA352i6L0KCc8yJs5NQPDDqVVZ2bOFr+QiU
8KMLAptr2TfAlb3zNhUGQuTxnGIfzLKoaRz3dtal3FLWV4UoyOMTh5KiX/I9O+wH
Vr1X7i9Ii+I4tR/56Ew0e+L5KoKR9W7SI/rdKogRBPoSQ0OcnVtY6+bm9SK6+49z
5YI+3N5kYCpyBtIKfP5kRQ2AdO1nB9Ezar4f2kI3zrlvp4+znPSBhLjmrODXpKfv
hRGbueA+jZ+J5lDsDgXe9qFfp3Z9crMSUQvdovhZeaBBBdhIVrBCNQ==
=xtJ0
- -----END PGP SIGNATURE-----
Reprinted with permission of Microsoft Corporation.
-
------------------------------------------------------------------------
----------
For additional information or assistance, please contact the HELP Desk
by
telephone or Not Protectively Marked information may be sent via EMail
to:
[EMAIL PROTECTED]
Tel: 020 7821 1330 Ext 4511
Fax: 020 7821 1686
-
------------------------------------------------------------------------
----------
UNIRAS wishes to acknowledge the contributions of Microsoft for the
information
contained in this Briefing.
-
------------------------------------------------------------------------
----------
This Briefing contains the information released by the original author.
Some
of the information may have changed since it was released. If the
vulnerability
affects you, it may be prudent to retrieve the advisory from the
canonical site
to ensure that you receive the most current information concerning that
problem.
Reference to any specific commercial product, process, or service by
trade
name, trademark manufacturer, or otherwise, does not constitute or imply
its endorsement, recommendation, or favouring by UNIRAS or NISCC. The
views
and opinions of authors expressed within this notice shall not be used
for
advertising or product endorsement purposes.
Neither UNIRAS or NISCC shall also accept responsibility for any errors
or omissions contained within this briefing notice. In particular, they
shall
not be liable for any loss or damage whatsoever, arising from or in
connection
with the usage of information contained within this notice.
UNIRAS is a member of the Forum of Incident Response and Security Teams
(FIRST)
and has contacts with other international Incident Response Teams (IRTs)
in
order to foster cooperation and coordination in incident prevention, to
prompt
rapid reaction to incidents, and to promote information sharing amongst
its
members and the community at large.
-
------------------------------------------------------------------------
----------
<End of UNIRAS Briefing>
-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com>
iQCVAwUBPfmzropao72zK539AQFmVwP/Wuc4veqggGUTmJ7+xI6cvLsluHvITWPI
GSSyksdniQvNB1oN4oMNS87sEwrcJ/PKWgsNp/9lXHYh+j+eqeJEg4qpCnHeVXuS
cDkOoQou9yROq/rVOTbEkvBlv1DBtTR7uNvzD7KQD6FS3J2gqcrgAO+JnUsnRxba
JR48J0PDpzg=
=WePz
-----END PGP SIGNATURE-----
IWS INFOCON Mailing List
@ IWS - The Information Warfare Site
http://www.iwar.org.uk
