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                     Secunia Research 18/02/2005

     - Yahoo! Messenger Audio Setup Wizard Privilege Escalation -

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Table of Contents

Affected Software....................................................1
Severity.............................................................2
Vendor's Description of Software.....................................3
Description of Vulnerability.........................................4
Solution.............................................................5
Time Table...........................................................6
Credits..............................................................7
References...........................................................8
About Secunia........................................................9
Verification........................................................10

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1) Affected Software 

Yahoo! Messenger 6.0.0.1750 (for Windows)

NOTE: Other versions may also be affected.

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2) Severity 

Rating: Less Critical 
Impact: Privilege Escalation
Where:  Local System

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3) Vendor's Description of Software 

Yahoo! Messenger:
"Yahoo! Messenger is a free instant messaging service that you can 
use to communicate with other people who also use Yahoo! Messenger".
 
Product link:
http://messenger.yahoo.com/

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4) Description of Vulnerability

Secunia Research has discovered a vulnerability in Yahoo! Messenger, 
which can be exploited by malicious, local users to gain escalated 
privileges.

The vulnerability is caused due to a combination of weak default 
directory permissions and the Audio Setup Wizard (asw.dll) invoking 
the "ping.exe" utility insecurely during the connection testing phase.

This can be exploited to execute arbitrary code with the privileges 
of another user by placing a malicious "ping.exe" file in the 
application's "Messenger" directory.

Successful exploitation requires that a user runs the Audio Setup 
Wizard and that the application has been installed in a non-default 
location (not as a subdirectory to the "Program Files" directory).

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5) Solution 

Vendor issued a fixed version on February 16, 2005.

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6) Time Table 

04/01/2005 - Vendor notified.
14/01/2005 - Vendor contacted second time.
17/01/2005 - Vendor response.
16/02/2005 - Vendor issues updated version.
18/02/2005 - Public disclosure.

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7) Credits 

Discovered by Carsten Eiram, Secunia Research.

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8) References

The Common Vulnerabilities and Exposures (CVE) project has assigned 
candidate number CAN-2005-0242 for the vulnerability.

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9) About Secunia 

Secunia collects, validates, assesses, and writes advisories regarding 
all the latest software vulnerabilities disclosed to the public. These 
advisories are gathered in a publicly available database at the 
Secunia website: 

http://secunia.com/

Secunia offers services to our customers enabling them to receive all 
relevant vulnerability information to their specific system 
configuration. 

Secunia offers a FREE mailing list called Secunia Security Advisories: 

http://secunia.com/secunia_security_advisories/

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10) Verification 

Please verify this advisory by visiting the Secunia web site:
http://secunia.com/secunia_research/2004-6/

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

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