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The U.S. Department of Energy
Computer Incident Advisory Capability
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INFORMATION BULLETIN
Microsoft Cumulative Patch for Internet Explorer (IE)
[Microsoft Security Bulletin MS03-020]
June 4, 2003 19:00 GMT Number N-101
______________________________________________________________________________
PROBLEM: There are two new vulnerabilities in Microsoft Internet
Explorer:
(1) A buffer overrun vulnerability that occurs because Internet
Explorer does not properly determine an object type returned
from a web server.
(2) A flaw that results because Internet Explorer does not
implement an appropriate block on a file download dialog box.
SOFTWARE: Microsoft Internet Explorer 5.01
Microsoft Internet Explorer 5.5
Microsoft Internet Explorer 6.0
Microsoft Internet Explorer 6.0 for Windows Server 2003
DAMAGE: These vulnerabilities could enable an attacker to execute
arbitrary code on a user's system if the user either browsed to
a hostile web site or opened a specially crafted HTML email
message.
SOLUTION: Apply patch as indicated in Microsoft's bulletin.
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VULNERABILITY The risk is MEDIUM. An attacker would have to host a web site
ASSESSMENT: or send a malicious email that contained a web page used to
exploit the particular vulnerability.
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LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-101.shtml
ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url=
/technet/security/bulletin/MS03-020.asp
PATCHES: http://www.microsoft.com/windows/ie/downloads/critical
/818529/default.asp
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[***** Start Microsoft Security Bulletin MS03-020 *****]
Microsoft Security Bulletin MS03-020
Cumulative Patch for Internet Explorer (818529)
Originally posted: June 4, 2003
Summary
Who should read this bulletin: Customers using Microsoft® Internet Explorer
Impact of vulnerability: Allow an attacker to execute code on a user’s system
Maximum Severity Rating: Critical
Recommendation: System administrators should install the patch immediately
End User Bulletin: An end user version of this bulletin is available at:
http://www.microsoft.com/security/security_bulletins/ms03-020.asp.
Affected Software:
Microsoft Internet Explorer 5.01
Microsoft Internet Explorer 5.5
Microsoft Internet Explorer 6.0
Microsoft Internet Explorer 6.0 for Windows Server 2003
Technical details
Technical description:
This is a cumulative patch that includes the functionality of all previously
released patches for Internet Explorer 5.01, 5.5 and 6.0. In addition, it
eliminates two newly discovered vulnerabilities:
A buffer overrun vulnerability that occurs because Internet Explorer does
not properly determine an object type returned from a web server. It could
be possible for an attacker who exploited this vulnerability to run arbitrary
code on a user's system. If a user visited an attacker’s website, it would
be possible for the attacker to exploit this vulnerability without any other
user action. An attacker could also craft an HTML email that attempted to
exploit this vulnerability.
A flaw that results because Internet Explorer does not implement an
appropriate block on a file download dialog box. It could be possible for
an attacker to exploit this vulnerability to run arbitrary code on a user's
system. If a user simply visited an attacker’s website, it would be possible
for the attacker to exploit this vulnerability without any other user action.
An attacker could also craft an HTML email that attempted to exploit this
vulnerability.
In order to exploit these flaws, the attacker would have to create a specially
formed HTML email and send it to the user. Alternatively an attacker would
have to host a malicious web site that contained a web page designed to
exploit these vulnerabilities. The attacker would then have to persuade a user
to visit that site.
As with the previous Internet Explorer cumulative patches released with
bulletins MS03-004 and MS03-015, this cumulative patch will cause
window.showHelp( ) to cease to function if you have not applied the HTML
Help update. If you have installed the updated HTML Help control from
Knowledge Base article 811630, you will still be able to use HTML Help
functionality after applying this patch.
Mitigating factors: The following mitigating factors apply to both
vulnerabilities discussed in this bulletin:
By default, Internet Explorer on Windows Server 2003 runs in Enhanced
Security Configuration. This default configuration of Internet Explorer
blocks these attacks. If Internet Explorer Enhanced Security Configuration
has been disabled, the protections put in place that prevent these
vulnerabilities from being exploited would be removed.
In the Web based attack scenario, the attacker would have to host a web
site that contained a web page used to exploit these vulnerabilities. An
attacker would have no way to force users to visit a malicious web site
outside of the HTML email vector. Instead, the attacker would need to lure
them there, typically by getting them to click on a link that would take
them to the attacker's site.
Code that executed on the system would only run under the privileges of the
logged in user.
Severity Rating:
Object Tag Vuln File Download Vuln
IE 5.01 SP3 Critical Critical
IE 5.5 SP2 Critical Critical
IE 6.0 Gold Critical Critical
IE 6.0 SP1 Critical Critical
IE 6.0 for Windows Server 2003 Moderate Moderate
The above assessment is based on the types of systems affected by the
vulnerability, their typical deployment patterns, and the effect that
exploiting the vulnerability would have on them. The moderate severity
rating on Windows Server 2003 is based on Internet Explorer Enhanced
Security Configuration.
Vulnerability identifier:
Object Tag Vulnerability: CAN-2003-0344
File Download Dialog Vulnerability: CAN-2003-0309
Tested Versions:
Internet Explorer versions 5.01 Service Pack 3, Internet Explorer 5.5 SP2,
Internet Explorer 6.0, Internet Explorer 6.0 SP1, and Internet Explorer 6.0
for Windows Server 2003 were tested for these vulnerabilities. Previous
versions are no longer supported, and may or may not be affected by these
vulnerabilities. More information on Windows Operating System Components
Lifecycles is available from:
http://microsoft.com/windows/lifecycle/desktop/consumer/components.mspx
Patch availability
Download locations for this patch
http://www.microsoft.com/windows/ie/downloads/critical/818529/default.asp
Additional information about this patch
Installation platforms:
IE5.01 running on Windows 2000 systems with Service Pack 3 installed.
The IE 5.5 patch can be installed on systems running Service Pack 2.
The IE 6.0 patch can be installed on systems running IE 6.0 Gold or
Service Pack 1.
Inclusion in future service packs:
The fix for these issues will be included in Windows XP Service Pack 2 and
Windows Server 2003 Service Pack 1
Reboot needed: Yes
Patch can be uninstalled: Yes
Superseded patches: This patch supersedes the one provided in Microsoft
Security Bulletin MS03-015, which is itself a cumulative patch.
Verifying patch installation:
To verify that the patch has been installed on the machine, open Internet
Explorer, select Help, then select About Internet Explorer and confirm that
Q818529 is listed in the Update Versions field.
Note that you can not use this method on Windows Server 2003 or Windows
XP 64-Bit Edition Version 2003, as the Update Versions field is not updated
by the package for these operating systems.
To verify the individual files, use the patch manifest provided in Knowledge
Base article 818529.
Caveats:
If you have not installed the updated HTML Help control from Knowledge Base
article 811630, you will not be able to use some HTML Help functionality after
applying this update. In order to restore that functionality, users need to
download the updated HTML Help control (811630). Users should also note that
when the latest version of HTML Help is installed, the following limitations
will occur when a help file is opened with the showHelp method:
Only supported protocols can be used with showHelp to open a web page or help
(chm) file.
The shortcut function supported by HTML Help will be disabled when the help
file is opened with showHelp This will not affect the shortcut functionality
if the same CHM file is opened by the user manually by double-clicking on the
help file, or by through an application on the local system using the
HTMLHELP( ) API.
Localization:
Localized versions of this patch are available at the locations discussed in
“Patch Availability”.
Obtaining other security patches:
Patches for other security issues are available from the following locations:
Security patches are available from the Microsoft Download Center, and can be
most easily found by doing a keyword search for "security_patch".
Patches for consumer platforms are available from the WindowsUpdate web site
Other information:
Acknowledgments
Microsoft thanks eEye Digital Security for reporting this issue to us and
working with us to protect customers.
Support:
Microsoft Knowledge Base article 818529 discusses this issue. Knowledge Base
articles can be found on the Microsoft Online Support web site.
Technical support is available from Microsoft Product Support Services.
There is no charge for support calls associated with security patches.
Scanning for Updates:
As part of Microsoft's Strategic Technology Protection Program, and in
response to direct customer need for a streamlined method of identifying
common security misconfigurations, Microsoft has developed the Microsoft
Baseline Security Analyzer (MBSA).
MBSA version 1.1.1 adds support for Windows Server 2003 and will be available
approximately 24 hours after the release of this bulletin at the following
location:
http://www.microsoft.com/technet/treeview/default.asp?url=
/technet/security/tools/Tools/MBSAhome.asp
Security Resources: The Microsoft TechNet Security Web Site provides
additional information about security in Microsoft products.
Disclaimer:
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.
Revisions:
V1.0 (June 4, 2003): Bulletin published.
[***** End Microsoft Security Bulletin MS03-020 *****]
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Microsoft Corporation for the
information contained in this bulletin.
_______________________________________________________________________________
CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193 (7x24)
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@ciac.org
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
World Wide Web: http://www.ciac.org/
Anonymous FTP: ftp.ciac.org
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
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