2 patch per Internet Explorer 4.0 e 5.0
Sono disponibili due patch per i Browser Internet Explorer 4.0 e 5.0
(solo su piattaforme Windows Intel) della Microsoft che risolvono alcuni
problemi di esposizione involontaria di informazioni: in tutti i casi
sarebbe possibile per un sito web malizioso ottenere informazioni ed
eventualmente sovrascrivere files sulla macchina client.
Di seguito sono indicati i puntatori alle due patch da installare.
********************************
Microsoft Security Bulletin (MS99-011)
--------------------------------------
Patch Available for "DHTML Edit" Vulnerability
Originally Posted: April 21, 1999
Summary
=======
Microsoft has released a patch that eliminates a vulnerability in an ActiveX
control that is distributed in Internet Explorer 5 and downloadable for
Internet Explorer 4.0. The vulnerability could allow a malicious web site
operator to read information that a user had loaded into the control, and it
also could allow files with known names to be copied from the user's local
hard drive.
A fully supported patch is available to eliminate this vulnerability and
Microsoft recommends that affected customers download and install it, if
appropriate.
Issue
=====
The DHTML Edit control is an ActiveX control that is distributed with
Internet Explorer 5 and can be downloaded for use in Internet Explorer 4.0.
The control enables users to edit HTML text and see a faithful rendition of
how the text would look in the browser. There are two versions of the
control: a more powerful version that cannot be invoked by a web site
because it includes file access and other features, and a "safe for
scripting" version that has restricted functionality and is intended for use
by web sites.
The root cause of the vulnerability lies in the fact that a web site that
hosts the "safe for scripting" version of the control is able to upload any
data entered into the control. A malicious web site operator could trick a
user into entering sensitive data into a DHTML Edit control hosted on a web
page from the operator's site, and then upload the data. In addition, if the
malicious web site operator knows the name of a file on the user's local
drive, it is possible for the operator to programmatically load the file
into the control and then upload it.
The patch works by allowing a web site to load data from the control only if
it is in the site's domain. While there are no reports of customers being
adversely affected by this vulnerability, Microsoft is proactively releasing
this patch to allow customers to take appropriate action to protect
themselves against it.
Affected Software Versions
==========================
- Microsoft Internet Explorer 5 on Windows 95, Windows 98, and
Windows NT 4.0. Internet Explorer 5 on other platforms is
not affected.
- Microsoft Internet Explorer 4.0 on Windows 95, Windows 98 and
the x86 version of Windows NT 4.0. Internet Explorer 4.0 on
other platforms, including the Alpha version of Windows NT 4.0,
is not affected.
Note: The DHTML Edit control is included by default in Internet Explorer 5.
It is not included by default in Internet Explorer 4.0, but can be
downloaded and installed. Internet Explorer 4.0 customers who are unsure
whether they have installed the control should see What Customers Should Do.
What Microsoft is Doing
=======================
Microsoft has released patches that fix the problem identified. The patches
are available for download from the sites listed below in What Customers
Should Do.
Microsoft also has sent this security bulletin to customers
subscribing to the Microsoft Product Security Notification Service.
See http://www.microsoft.com/security/services/bulletin.asp for
more information about this free customer service.
Microsoft has published the following Knowledge Base (KB) article on this
issue:
- Microsoft Knowledge Base (KB) article Q226326,
Update Available for 'DHTML Edit' Security Issue,
http://support.microsoft.com/support/kb/articles/q226/3/26.asp.
(Note: It might take 24 hours from the original posting of this
bulletin for the KB article to be visible in the Web-based
Knowledge Base.)
What Customers Should Do
========================
Microsoft highly recommends that customers determine whether they are
potentially affected by the vulnerability:
- All copies of Internet Explorer 5 contain the DHTML Edit
control, so all Internet Explorer 5 customers are potentially
affected by the vulnerability.
- The only Internet Explorer 4.0 users who are potentially
affected by the vulnerability are those who have downloaded
and installed the DHTML Edit control. If this has been done,
the file dhtmled.ocx will be present on the hard drive. By
default, this file will be stored in the folder
C:Program FilesCommon FilesMicrosoft SharedTriedit.
Customers who are potentially affected by the vulnerability should
evaluate the degree of risk that this vulnerability poses to their
systems and determine whether to download and install the patch.
The patch can be found at
http://www.microsoft.com/windows/ie/security/dhtml_edit.asp.
More Information
================
Please see the following references for more information related to this
issue.
- Microsoft Security Bulletin MS99-011,
Patch Available for DHTML Edit Vulnerability.
(The Web-posted version of this bulletin),
http://www.microsoft.com/security/bulletins/ms99-011.asp.
- Microsoft Knowledge Base (KB) article Q226326,
Update Available for 'DHTML Edit' Security Issue,
http://support.microsoft.com/support/kb/articles/q226/3/26.asp.
(Note: It might take 24 hours from the original posting of
this bulletin for the KB article to be visible in the Web-based
Knowledge Base.)
********************************
Microsoft Security Bulletin (MS99-012)
--------------------------------------
MSHTML Update Available for Internet Explorer
Originally Posted: April 21, 1999
Summary
=======
Microsoft has released an updated version of a component of Internet
Explorer 4.0 and 5. The updated version eliminates three security
vulnerabilities described below. It is fully supported and Microsoft
recommends that affected customers download and install it, if appropriate.
Issue
=====
MSHTML.DLL is the parsing engine for HTML in Internet Explorer. The
vulnerabilities that are eliminated by the update are not related to each
other except for the fact that all reside within the parsing engine.
- The first vulnerability is a privacy issue involving
the processing of the "IMG SRC" tag in HTML files. This tag
identifies and loads image sources - image files that are
to be displayed as part of a web page. The vulnerability
results because the tag can be used to point to files of any
type, rather than only image files, after which point the
document object model methods can be used to determine information
about them. A malicious web site operator could use this vulnerability
to determine the size and other information about files on the
computer of a visiting user. It would not allow files to be read or
changed, and the malicious web site operator would need to know the
name of each file.
- The second vulnerability is a new variant of a previously-identified
cross-frame security vulnerability. A particular malformed URL could
be used to execute scripts in the security context of a different
domain. This could allow a malicious web site operator to execute a
script on the web site, and gain privileges on visiting users' machines
that are normally granted only to their trusted sites.
- The third vulnerability affects only Internet Explorer 5.0, and is a
new variant of a previously-identified untrusted scripted paste
vulnerability. The vulnerability would allow a malicious web site
operator to create a particular type of web page control and paste
into it the contents of a visiting user's clipboard.
While there are no reports of customers being adversely affected by any of
these vulnerabilities, Microsoft is proactively releasing an updated version
of MSHTML.DLL to allow customers to take appropriate action to protect
themselves against it.
Affected Software Versions
==========================
- Internet Explorer 4.0 and 5 on Windows 95, Windows 98
and Windows NT 4.0.
What Microsoft is Doing
=======================
Microsoft has released patches that fix the problem identified. The patches
are available for download from the sites listed below in What Customers
Should Do.
Microsoft also has sent this security bulletin to customers
subscribing to the Microsoft Product Security Notification Service.
See http://www.microsoft.com/security/services/bulletin.asp for
more information about this free customer service.
Microsoft has published the following Knowledge Base (KB) article on this
issue:
- Microsoft Knowledge Base (KB) article Q226326,
Update Available for MSHTML Security Issues in Internet Explorer,
http://support.microsoft.com/support/kb/articles/q226/3/26.asp.
(Note: It might take 24 hours from the original posting of this
bulletin for the KB article to be visible in the Web-based Knowledge
Base.)
What Customers Should Do
========================
Microsoft highly recommends that customers evaluate the degree of
risk that this vulnerability poses to their systems and determine
whether to download and install the patch. The patch can be found at
http://www.microsoft.com/windows/ie/security/mshtml.asp.
More Information
================
Please see the following references for more information related to this
issue.
- Microsoft Security Bulletin MS99-012,
MSHTML Update Available for Internet Explorer (The Web-posted
version of this bulletin),
http://www.microsoft.com/security/bulletins/ms99-012.asp.
- Microsoft Knowledge Base (KB) article Q226326,
Update Available for MSHTML Security Issues in Internet Explorer,
http://support.microsoft.com/support/kb/articles/q226/3/26.asp.
- Microsoft Security Bulletin MS98-013,
Fix available for Internet Explorer Cross Frame Navigate Vulnerability,
http://www.microsoft.com/security/bulletins/ms98-013.asp
- Microsoft Security Bulletin MS98-015,
Update available for "Untrusted Scripted Paste" Issue in Microsoft
Internet Explorer 4.01,
http://www.microsoft.com/security/bulletins/ms98-015.asp