M$ patch can lock users out of Web sites

[drag0nsfyre]

Hey All,

A recent Microsoft Corp. security patch for Internet Explorer (IE) can lock users out of certain Web sites and Microsoft's own MSN e-mail service, Microsoft said late Wednesday.

The issue affects the cumulative patch for IE versions 5.01, 5.5 and 6.0 released on Feb. 5 and rated "critical" by Microsoft. The software maker released a software fix to correct the bug, according to the revised MS03-004 security bulletin. http://www.microsoft.com/technet/sec...n/MS03-004.asp

Full story Here

I havnt personally experienced any problems myself , but just in case any of you have I thought this may be of some use when i read it

[Sevari]

I wonder what websites they blocked *cough*opensource.org*cough*

[thehorse13]

Yeah, I haven't seen this issue pop up yet either.

Here is another site reporting this issue:

http://www.entmag.com/news/article.a...torialsID=5698

[AciDriveHB]

Yeah really, something like that from Microsoft doesn't sound like it wans't planned. They probably just had someone complain about it, and rather than looking like @$$es they said... "Oh it must be a problem with the software, we'll get a patch out ASAP". Oh god, that is almost so funny it should be in the tech humor section!

[GandalfTheGray]

This may be the MS patch to address the issue.

- ----------------------------------------------------------------------
Title: Cumulative Patch for Internet Explorer (810847)
Released: 5 February 2003
Revised: 12 February 2003(version 2.0)
Software: Microsoft Internet Explorer 5.01
Microsoft Internet Explorer 5.5
Microsoft Internet Explorer 6.0
Impact: Allow an attacker to execute commands on a user's
system.
Max Risk: Critical
Bulletin: MS03-004

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/sec...n/MS03-004.asp
http://www.microsoft.com/security/se...s/ms03-004.asp
- ----------------------------------------------------------------------

Reason for Revision:
====================
Subsequent to the initial release of this bulletin, a non-security
issue was discovered with this patch that could affect some users -
primarily consumers - under certain conditions. Specifically, the
issue could cause some users to be unable to authenticate to
certain Internet web sites such as subscription based sites, or MSN
e-mail. This issue has been resolved, and a hot fix (813951) issued
to correct it. It is important to note that this hot fix corrects a
very specific non-security issue, and that the security patch
discussed in this Security Bulletin was, and still is, effective in
removing the vulnerabilities discussed later in this bulletin. More
information, including details of how to obtain the hot fix are
available at:
http://www.microsoft.com/windows/ie/...l/813951/defau
lt.asp and in the Frequently Asked Questions section of this
bulletin.

Issue:
======

This is a cumulative patch that includes the functionality of all
previously released patches for IE 5.01, 5.5, 6.0. In addition, it
eliminates two newly discovered vulnerabilities involving Internet
Explorer's cross-domain security model - which keeps windows of
different domains from sharing information. These flaws results in
Internet Explorer because incomplete security checking causes
Internet Explorer to allow one website to potentially access
information from another domain when using certain dialog boxes.
In order to exploit this flaw, an attacker would have to host a
malicious web site that contained a web page designed to exploit
this particular vulnerability and then persuade a user to visit
that site. Once the user has visited the malicious web site, it
would be possible for the attacker to run malicious script by
misusing a dialog box and cause that script to access information
in a different domain. In the worst case, this could enable the web
site operator to load malicious code onto a user's system. In
addition, this flaw could also enable an attacker to invoke an
executable that was already present on the local system.

A related cross-domain vulnerability allows Internet Explorer's
showHelp() functionality to execute without proper security
checking. showHelp() is one of the help methods used to display an
HTML page containing help content. showHelp() allows more types of
pluggable protocols than necessary, and this could potentially
allow an attacker to access user information, invoke executables
already present on a user's local system or load malicious code
onto a user's local system.

The requirements to exploit this vulnerability are the same as for
the issue described above: an attacker would have to host and lure
a user to a malicious web site. In this scenario, the attacker
could open a showHelp window to a known local file on the visiting
user's local system and gain access to information from that file
by sending a specially crafted URL to a second showHelp window. The
attacker could also potentially access user information or run code
of attacker's choice.

This cumulative patch will cause window.showHelp( ) to cease to
function. When the latest HTML Help update - which is being
released via Windows Update with this patch - is installed,
window.showHelp( ) will function again, but with some limitations
(see the caveats section later in this bulletin). This has been
necessary in order to block the attack vector that might allow a
web site operator to invoke an executable that was already present
on a user's local system.

Mitigating Factors:
====================
- -The attacker would have to host a web site that contained a
web page used to exploit either of these cross-domain
vulnerabilities.
- -The attacker would have no way to force users to visit the
site. 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.
- -By default, Outlook Express 6.0 and Outlook 2002 open HTML
mail in the Restricted Sites Zone. In addition, Outlook 98 and 2000
open HTML mail in the Restricted Sites Zone if the Outlook Email
Security Update has been installed. Customers who use any of these
products would be at no risk from an e-mail borne attack that
attempted to exploit this vulnerability unless the user clicked a
malicious link in the email.
- -Internet Explorer 5.01 users are not affected by the first
vulnerability.

Risk Rating:
============
- Critical

Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletins at
http://www.microsoft.com/technet/sec...n/ms03-004.asp
http://www.microsoft.com/security/se...s/ms03-004.asp
for information on obtaining this patch.

Acknowledgment:
===============
- Microsoft thanks Andreas Sandblad, Sweden for reporting the
cross domain vulnerability using showHelp and for working with us
to protect customers.

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

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