Secunia Research: Microsoft Windows usp10.dll "GetFontDesc()" Integer Underflow Vulnerability

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                    Secunia Research 08/12/2015              

             Microsoft Windows usp10.dll "GetFontDesc()"
                  Integer Underflow Vulnerability

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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


* Microsoft Windows 7
* Microsoft Windows Server 2008

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2) Severity 

Rating: Highly critical
Impact: System Access
Where:  From remote
 
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3) Description of Vulnerability

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

The vulnerability is caused due to an integer underflow error within
the "GetFontDesc()" function in usp10.dll when processing font files
cmap table and can be exploited to cause a heap-based buffer overflow
via a font file containing cmap table data with specially crafted
offset within encoding records.

Successful exploitation allows execution of arbitrary code.

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4) Solution 

Apply update provided by MS15-130.

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5) Time Table

09/10/2015 - Vendor notified.
12/10/2015 - Vendor response.
17/10/2015 - Status update provided by the vendor.
28/10/2015 - Vendor provides December 2015 as intended fix date.
08/12/2015 - Release of vendor patch and public disclosure.

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6) Credits 

Discovered by Hossein Lotfi, Secunia Research (now part of
Flexera Software).

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7) References


The Common Vulnerabilities and Exposures (CVE) project has assigned
the CVE-2015-6130 identifier for the vulnerability.
 
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8) About Secunia (now part of Flexera Software)

In September 2015, Secunia has been acquired by Flexera Software:

https://secunia.com/blog/435/

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

http://secunia.com/products/

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.

http://secunia.com/advisories/

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:

http://secunia.com/secunia_research/

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

http://secunia.com/company/jobs/

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9) Verification 

Please verify this advisory by visiting the Secunia website:
http://secunia.com/secunia_research/2015-6/

Complete list of vulnerability reports published by Secunia Research:
http://secunia.com/secunia_research/

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