Secunia Research: Opera Download Dialog Spoofing Vulnerability

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                     Secunia Research 28/07/2005

           - Opera Download Dialog Spoofing Vulnerability -

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Table of Contents

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

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1) Affected Software

Opera 8.01 for Windows

Prior versions may also be vulnerable.

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2) Severity

Rating: Moderately critical
Impact: Spoofing
Where:  From remote

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3) Description of Vulnerability

Secunia Research has discovered a vulnerability in Opera, which can 
be exploited by malicious people to trick users into executing 
malicious files.

The vulnerability is caused due to an error in the handling of 
extended ASCII codes in the download dialog. This can be exploited to 
spoof the file extension in the file download dialog via a specially 
crafted "Content-Disposition" HTTP header.

Successful exploitation may result in users being tricked into 
executing a malicious file via the download dialog, but requires that 
the "Arial Unicode MS" font (ARIALUNI.TTF) has been installed on the 
system.

NOTE: The "Arial Unicode MS" font is installed with various 
Microsoft Office distributions.

The vulnerability has been confirmed in version 8.01. Other versions 
may also be affected.

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4) Solution

Update to version 8.02.
http://www.opera.com/download/

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5) Time Table

29/06/2005 - Vulnerability discovered.
05/07/2005 - Vendor notified.
21/07/2005 - Vendor confirms the vulnerability.
28/07/2005 - Public disclosure.

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6) Credits

Discovered by Andreas Sandblad, Secunia Research.

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7) 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 web site:

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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8) Verification

Please verify this advisory by visiting the Secunia web site:
http://secunia.com/secunia_research/2005-25/advisory/

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