Secunia Research Advisory

Internet Explorer File Download Handling Memory Corruption


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                     Secunia Research 09/10/2007

    - Internet Explorer File Download Handling Memory Corruption -

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Table of Contents

Affected Software....................................................1
Severity.............................................................2
Description of Vulnerability.........................................3
Solution.............................................................4
Time Table...........................................................5
Credits..............................................................6
References...........................................................7
About Secunia........................................................8
Verification.........................................................9

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1) Affected Software 

* Internet Explorer 5.01
* Internet Explorer 6
* Internet Explorer 7

NOTE: Other versions may also be affected.

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2) Severity 

Rating: Highly critical
Impact: System compromise
Where:  Remote

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3) Description of Vulnerability

Secunia Research has discovered a vulnerability in Internet Explorer,
which can be exploited by malicious people to compromise a user's
system.

The vulnerability is caused due to an error in the file download queue
handling when processing multiple concurrent attempts to start a file
download. This can be exploited via a specially crafted web page to
corrupt memory in a way that results in use of an already freed 
object.

Successful exploitation allows execution of arbitrary code.

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4) Solution 

Apply patches (see Microsoft security bulletin for details).

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5) Time Table 

04/01/2007 - Vendor notified.
04/01/2007 - Vendor response.
09/10/2007 - Public disclosure.

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6) Credits 

Discovered by Carsten Eiram, Secunia Research.

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7) References

The Common Vulnerabilities and Exposures (CVE) project has assigned 
CVE-2007-3893 for the vulnerability.

MS07-057 (KB939653):
http://www.microsoft.com/technet/security/Bulletin/MS07-057.mspx

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8) About Secunia

Secunia offers vulnerability management solutions to corporate
customers with verified and reliable vulnerability intelligence
relevant to their specific system configuration:

https://www.flexera.com/

Secunia also provides a publicly accessible and comprehensive advisory
database as a service to the security community and private 
individuals, who are interested in or concerned about IT-security.

Secunia believes that it is important to support the community and to
do active vulnerability research in order to aid improving the 
security and reliability of software in general.

Secunia regularly hires new skilled team members. Check the URL below
to see currently vacant positions:

https://www.flexera.com/company/careers

Secunia offers a FREE mailing list called Secunia Security Advisories:

https://www.flexera.com/secunia_security_advisories/ 

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9) Verification 

Please verify this advisory by visiting the Secunia website:
https://www.flexera.com/about-us/secunia-research/advisories/sr-2007-31.html

Complete list of vulnerability reports published by Secunia Research:
https://www.flexera.com/about-us/secunia-research/advisories/

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