[SNS Advisory No.75] Webmin/Usermin Account Lockout Bypass Vulnerability

[snsadv () lac co jp (snsadv)]

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SNS Advisory No.75
Webmin/Usermin Account Lockout Bypass Vulnerability

Problem first discovered on: Sun, 11 Apr 2004
Published on: Fri, 11 Jun 2004
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Overview:
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  A vulnerability that could result in account lockout bypassing exists 
  in both Webmin and Usermin.


Problem Description:
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  Webmin is a web-based system administration tool for Unix.  Usermin 
  is a web interface that allows all users on a Unix system to easily
  receive mails and to perform SSH and mail forwarding configuration.

  Both Webmin and Usermin ship with an account lockout functionality,
  which fails to parse certain character strings.  By bypassing this
  functionality, attackers can attempt to guess IDs and passwords
  continuously, prevent legitimate users from logging on, etc.


Tested Versions:
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  Webmin Version 1.140
  Usermin Version 1.070


Solution:
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  This problem can be eliminated by upgrading to Webmin version 1.150
  and to Usermin version 1.080, which are available at:

    http://www.webmin.com/ 

Discovered by:
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  Keigo Yamazaki


Acknowledgements:
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  Mr. Jamie Cameron


Disclaimer: 
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  The information contained in this advisory may be revised without prior 
  notice and is provided as it is. Users shall take their own risk when 
  taking any actions following reading this advisory. LAC Co., Ltd. shall 
  take no responsibility for any problems, loss or damage caused by, or by 
  the use of information provided here.

  This advisory can be found at the following URL:
  http://www.lac.co.jp/security/csl/intelligence/SNSadvisory_e/75_e.html

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Computer Security Laboratory, LAC  http://www.lac.co.jp/security/