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From: <no...@so...> - 2001-08-15 06:42:39
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Feature Requests item #451087, was opened at 2001-08-14 23:42 You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=403614&aid=451087&group_id=31885 Category: None Group: None Status: Open Priority: 3 Submitted By: Richard Archer (richardarcher) Assigned to: Nobody/Anonymous (nobody) Summary: secure passwords in new_user_md5.php3 Initial Comment: reposted from mailing list Note: this deficiency is documented in the code. At 3:28 PM -0700 16/8/00, Torrey Hoffman wrote: >Hello. I'm using phplib 7.2b, with the md5 based challenge-response >authentication system. (Challenge_Crypt_Auth). > >I have a concern about password security for administrators adding users, or >changing user passwords. > >First, some background, as I understand it: > >The MD5 challenge-response authentication system is reasonably secure, even >over insecure networks, as it never sends passwords in the clear. It works >by using the JavaScript implementation of MD5 on the client to compute: >MD5("$username:$pass:$challenge"), where $pass is actually the md5 hash of >the plaintext password. > >Both the client and the server can compute this value, allowing the server >to authenticate the client. Since the $challenge is different for every >session, an eavesdropper (packet sniffer) cannot gain any useful knowledge >of the password, even though they can see the $username and $challenge. > >So all is well for authentication. > >But when adding a new user, the "\pages\admin\new_user_md5.php3" sample code >ends up passing the just md5(plaintext-password) over the network. If an >attacker grabs that information, then they can easily compute >md5("$username:$pass:$challenge) and falsify their authentication. As I see >it, there is no extra security in sending the MD5 hash of the plaintext >password when changing or setting passwords - you might as well just send >the plaintext password. > >I can't figure out an easy way to fix this without going with the full >Diffie-Hellman key exchange protocol. (See >http://www.apocalypse.org/pub/u/seven/diffie.html). However, I am not a >cryptography expert. > >So my questions are: > >1. Is there a secure way to set Challenge_Crypt_Auth MD5 passwords over the >net? >2. If so, has it been implemented somewhere with free source? >3. If not, is there some fundamental reason? Is this is hard to do with >JavaScript on the client and PHP on the server? >3. Is this weakness in the PHPLIB sample code documented? > >Thanks very much for any help or advice you can give. > >Tor...@my... > >PS: Huge thanks to the authors of PHPLIB for writing such an amazingly >useful piece of code. > ---------------------------------------------------------------------- You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=403614&aid=451087&group_id=31885 |
