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                     Secunia Research 26/06/2007

     - KVIrc irc:// URI Handler Command Execution Vulnerability -

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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 

* KVIrc 3.2.0

NOTE: Other versions may also be affected.

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2) Severity 

Rating: Moderately critical
Impact: System Access
Where:  Remote

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3) Vendor's Description of Software 

"KVIrc is a free portable IRC client based on the excellent Qt GUI
toolkit. KVIrc is being written by Szymon Stefanek and the KVIrc
Development Team with the contribution of many IRC addicted developers
around the world.".

Product Link: http://www.kvirc.net

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4) Description of Vulnerability

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

The vulnerability is caused due to the "parseIrcUrl()" function in
src/kvirc/kernel/kvi_ircurl.cpp not properly sanitising parts of the
URI when building the command for KVIrc's internal script system. This
can be exploited to inject and execute commands for the KVIrc script
system (including the "run" command, which can be leveraged to execute
shell commands) by e.g. tricking a user into opening a specially
crafted "irc://" or similar URI (e.g. "irc6://").

Successful exploitation requires that KVIrc is the default handler for
"irc://" and similar URIs.

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5) Solution 

Fixed in the SVN repository.
https://svn.kvirc.de/kvirc/changeset/630/#file3

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6) Time Table 

19/06/2007 - Vendor notified.
19/06/2007 - Vendor response.
21/06/2007 - Vendor commits fix into SVN repository.
26/06/2007 - Public disclosure.

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7) Credits 

Discovered by Stefan Cornelius, Secunia Research.

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8) References

The Common Vulnerabilities and Exposures (CVE) project has assigned 
CVE-2007-2951 for the vulnerability.

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9) About Secunia

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

http://corporate.secunia.com/

Secunia also provides a publicly accessible and comprehensive advisory
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individuals, who are interested in or concerned about IT-security.

http://secunia.com/

Secunia believes that it is important to support the community and to
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security and reliability of software in general:

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Secunia regularly hires new skilled team members. Check the URL below
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http://secunia.com/secunia_vacancies/

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 website:
http://secunia.com/secunia_research/2007-56/

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

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