RE: Windows 2000 password policy bypass possibility

From: Bradley, Tony (tony.bradleyat_private)
Date: Fri Mar 08 2002 - 15:33:25 PST

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    The password history check *should* still be performed from what I know, but
    it is possible for a user to simply go through and change their password 18
    times so they can use the old one again.
    
    To combat this you also need to set a minimum password age in your policy.
    If you set the minimum password age to 1 month they will not be able to
    reset their password for at least 1 month each time and then you guarantee
    that it will be 18 months until they can re-use the old password again.
    
    Tony Bradley, MCSE, MCSA, MCP, A+
    Threat & Vulnerability Monitor
    EDS GM Global Information Protection Programme
    
    "The price of success is hard work, dedication to the job at hand, and the
    determination that whether we win or lose, we have applied the best of
    ourselves to the task at hand."  ~ Vince Lombardi ~
    
      
    
    
    
    -----Original Message-----
    From: Leonid Mamtchenkov [mailto:leonidat_private]
    Sent: Thursday, March 07, 2002 2:41 AM
    To: bugtraqat_private
    Subject: Windows 2000 password policy bypass possibility
    
    
    Hello All,
    
    I have noticed the following behavior with Windows 2000 and I am not
    yet sure whether that is a bug or a feature.
    
    It is possible to create a security policy regarding passwords for
    Windows 2000, that will require users to use secure passwords, which
    should be periodically changed.  It is also possible to make Windows
    remember several previous passwords (18 in our case).
    
    Now, when time comes for user to change the password, system checks
    whether or not new password is among those 18 old ones.  If it is not,
    and password satisfies other conditions, then password changes.
    
    It is possible for user though to change the password without waiting
    for it to expire.  When changing this password, password history check
    is not done, but check for all other conditions is performed.
    
    Is this issue serious enough to be forwarded to Microsoft, or is it
    supposed to work this way?
    
    -- 
    Best regards,
      Leonid Mamtchenkov, RHCE
      System Administrator
      Francoudi & Stephanou Ltd.
    



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