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                     Secunia Research 13/10/2005

 - AhnLab V3 Antivirus ALZ/UUE/XXE Archive Handling Buffer Overflow -

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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 

AhnLab V3Pro 2004 (V3 VirusBlock 2005 international) (Build 6.0.0.457)
AhnLab V3Net for Windows Server 6.0 (Build 6.0.0.457)
AhnLab MyV3 with AzMain.dll 1.3.11.15

Prior versions may also be affected.

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2) Severity 

Rating: Highly critical
Impact: System access
Where:  Remote

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3) Description of Vulnerability

Secunia Research has discovered a vulnerability in AhnLab V3 
Antivirus, which can be exploited by malicious people to compromise
a vulnerable system.

The vulnerability is caused due to a boundary error in the archive
decompression library when reading the filename of a compressed file 
from an ALZ, UUE or XXE archive. This can be exploited to cause a 
stack-based buffer overflow (ALZ), or a heap-based buffer overflow
(UUE/XXE), when a malicious ALZ/UUE/XXE archive is scanned.

Successful exploitation allows arbitrary code execution, but requires 
that compressed file scanning is enabled.

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4) Solution 

AhnLab V3Pro 2004 (V3 VirusBlock 2005 international):
Update to version 6.0.0.488 via Smart Update.

AhnLab V3Net for Windows Server 6.0:
Update to version 6.0.0.488 via Smart Update.

AhnLab MyV3:
The vulnerability has reportedly been fixed in the vendor's Korean
MyV3 website.

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5) Time Table 

19/09/2005 - Initial vendor notification.
20/09/2005 - Initial vendor response.
13/10/2005 - Vendor releases advisory.
13/10/2005 - Public disclosure.

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6) Credits 

Discovered by Tan Chew Keong, Secunia Research.

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7) References

AhnLab:
http://global.ahnlab.com/security/security_advisory002.html

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8) 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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9) Verification 

Please verify this advisory by visiting the Secunia website:
http://secunia.com/secunia_research/2005-48/advisory/

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

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