From: Secunia Security Advisories (sec-advsecunia.com)
Date: Fri Jan 07 2005 - 04:53:02 CST

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TITLE:
Microsoft Internet Explorer Multiple Vulnerabilities

SECUNIA ADVISORY ID:
SA12889

VERIFY ADVISORY:
http://secunia.com/advisories/12889/

CRITICAL:
Extremely critical

IMPACT:
Security Bypass, Cross Site Scripting, System access

WHERE:
From remote

REVISION:
5.0 originally posted 2004-10-20

SOFTWARE:
Microsoft Internet Explorer 6
http://secunia.com/product/11/

DESCRIPTION:
Some vulnerabilities have been discovered in Internet Explorer, which
can be exploited by malicious people to compromise a user's system,
conduct cross-site/zone scripting and bypass a security feature in
Microsoft Windows XP SP2.

1) Insufficient validation of drag and drop events from the
"Internet" zone to local resources for valid images or media files
with embedded HTML code. This can be exploited by e.g. a malicious
web site to plant arbitrary HTML documents on a user's system, which
may allow execution of arbitrary script code in the "Local Computer"
zone.

This vulnerability is a variant of:
SA12321

NOTE: Microsoft Windows XP SP2 does not allow Active Scripting in the
"Local Computer" zone.

2) A security site / zone restriction error, where an embedded HTML
Help control on e.g. a malicious web site references a specially
crafted index (.hhk) file, can execute local HTML documents or inject
arbitrary script code in context of a previous loaded document using a
malicious javascript URI handler.

Successful exploitation may allow execution of arbitrary HTML and
script code in a user's browser session in context of arbitrary
sites, or execution of local programs with parameters from the "Local
Computer" zone using a HTML Help shortcut.

NOTE: This will bypass the "Local Computer" zone lockdown security
feature in SP2.

3) A security site / zone restriction error in the handling of the
"Related Topics" command in an embedded HTML Help control can be
exploited by e.g. a malicious website to execute arbitrary script
code in the context of arbitrary sites or zones.

NOTE: This may be exploited to bypass the "Local Computer" zone
lockdown security feature in SP2.

Secunia has constructed a test, which can be used to check if your
browser is affected by this issue:
http://secunia.com/internet_explorer_command_execution_vulnerability_test/

Vulnerability 1 and 2, or 3 alone, in combination with an
inappropriate behaviour where the ActiveX Data Object (ADO) model can
write arbitrary files can be exploited to compromise a user's system.
This has been confirmed on a fully patched system with Internet
Explorer 6.0 and Microsoft Windows XP SP2.

SOLUTION:
Use another product.

Alternative workarounds:
1) The vendor recommends that the "Drag and drop or copy and paste
files" option is disabled.
2, 3) Set security level to high for the "Internet" zone.

PROVIDED AND/OR DISCOVERED BY:
1) Discovered independently by:
* http-equiv
* Andreas Sandblad of Secunia Research (reported to Microsoft on
2004-10-13).

2) Discovered by:
* http-equiv

Additional information provided by:
* Roozbeh Afrasiabi

3) Discovered by:
* Paul, Greyhats Security
* Michael Evanchik

Additional information provided by:
* ShredderSub7

CHANGELOG:
2004-10-21: Updated advisory.
2004-10-28: Added another workaround in "Solution" section and linked
to Microsoft Knowledge Base article.
2004-11-02: Updated with additional information in "Description" and
"Solution" section.
2004-11-29: Updated "Description" section with additional information
from Paul.
2004-12-23: Added link to US-CERT vulnerability note.
2004-12-25: Updated "Description" section with additional information
from Paul and Michael Evanchik.
2005-01-07: Increased rating. Added link to test. Updated
"Description" and "Solution" sections.

ORIGINAL ADVISORY:
3) http://freehost07.websamba.com/greyhats/sp2rc-analysis.htm

OTHER REFERENCES:
SA12321:
http://secunia.com/advisories/12321/

How to Disable "Drag and Drop or copy and paste files" option in
Internet Explorer:
http://support.microsoft.com/kb/888534

How to Disable Active Content in Internet Explorer:
http://support.microsoft.com/default.aspx?scid=kb;en-us;q154036

US-CERT VU#939688:
http://www.kb.cert.org/vuls/id/939688

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