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Re: How secure is Email based password reset?
From: "S. Rohit" <s.rohit () usa net>
Date: Sat, 10 May 2003 11:02:58 +0800

hi....

    This is a very neat and elegant solution proposed by Dan. The only
problem in this solution can be to ensure that the SSL session does not time
out before the email is recieved by the user. This can happen because it
mite be possible for the email to get delyaed in delivery, which is quite a
common occurrence. Especially if the mail server that u will be using to
send out the email will be the same as the corporate email server. To ensure
that this solution works in a more smoother manner u mite want to consider
adding in a new mail server intot he solution which can handle the outgoing
emails from all the applications that will be using this kind of solution.
This will atleast reduce the lag in email transit introduced due to the load
on the corporate email servers..... Now the only reason for delated email
deliver will be internet traffic based delays....

rohit

----- Original Message ----- 
From: "Dan Kubb" <dan.kubb () marketingtips com>
To: "'Shekhar Jha'" <shekhar-jha () usa net>
Cc: <security-basics () securityfocus com>
Sent: Friday, May 09, 2003 12:18 AM
Subject: RE: How secure is Email based password reset?


I'd do the following:

  1. When generating the user account, ask them to enter
     in a personal question that only they would know the
     answer to.  I'd then ask them to put in the answer.
     I'd also instruct them on bad questions, like
     "What is my SSN?" Or "What is my mother's maiden name?".
  2. SHA-1 hash their answer and store it in the database.
  3. When the user tries to log in, and forgets their
     password redirect them to an SSL protected area.
  4. Ask them the "secret question".  Hash their answer, and
     compare against the DB.  If they get it right,
     email a one-time "key".
  5. Tell the user to check their email, and paste in the
     key that was just mailed to them into a text box and
     hit submit.  Most importantly:  All this is done during
     the same SSL session, and the one-time key is only valid
     for this SSL session and for a limited time (say 5 mins).
     If the user disconnects, or walks away from their
     computer for more than 5 mins, the key should be made
     not to work.
  6. User gets to change their password from within an SSL
     enabled area.

Step number 5 is the important one.  If someone intercepted
the passphrase in-transit, they wouldn't be able to do
anything with it, because its only valid for the real
user's SSL session.

You could probably change it so that instead of pasting
in a text box, that they click on a link via email.  The
only important factor is that the current SSL session is
used so we can prove the person clicking on the link is
the same person who got the answer correct.

Dan Kubb
Lead Software Developer
The Internet Marketing Center


One of the ways to implement the password reset is to
1. Ask the personal question
2. if correctly answered, generates a unique temporary password
3. Send the password over email to user.
4. This would allow user to login once.

My query is regarding sending the password over email to
user. How secure is
it? Given that,
1. The Server would be delivering the password email to an
Internet Service
Provider.
2. The user would typically be online waiting for the password emal to
arrive.
3. The password would be invalid after the first use.
How valid are these assumptions?

Any other pointers about different way of re-setting the
password would be
helpful.


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---------------------------------------------------------------------------
FastTrain has your solution for a great CISSP Boot Camp. The industry's most 
recognized corporate security certification track, provides a comprehensive 
prospectus based upon the core principle concepts of security. This ALL INCLUSIVE curriculum utilizes lectures, case 
studies and true hands-on utilization 
of pertinent security tools. For a limited time you can enter for a chance 
to win one of the latest technological innovations, the SEGWAY HT. 
Log onto http://www.securityfocus.com/FastTrain-security-basics 
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