> On Tue, Apr 02, 2002 at 04:43:43PM -0600, McNutt, Justin M. wrote:
> > Okay, so the way that Microsoft's RADIUS server gets away 
> with this is due to the fact that in a Microsoft domain, user 
> names and passwords are not stored using strong (one-way) 
> encryption.  You can decrypt the password file.
> > 
> 
> No.  Microsoft stores a cleartext equivalent of the password.

In terms of being able to get the cleartext password itself, this is the same thing.  
While unix stores a one-way encrypted version of your password, Microsoft stores a 
hash that can be trivially defeated.

> > So when an EAP request comes in to an MS RADIUS server, MS 
> decrypts your password, then encrypts it again using EAP-MD5, 
> which it can then check against the string that came from the NAS.
> 
> No, it hashes the cleartext equivalant the same way the client does.
> It then compares the two hashes.

Again, same idea.  MS uses the repository of password-equivalent strings that are 
stored in Active Directory, the NT domain, whatever to compare against the 
authentication string provided in the EAP request.

The problem I have with all of this is the fact that the actual passwords can be 
deduced using the "cleartext equivalent" that MS stores.  This is a huge weakness in 
NT/2K-based authentication that I was hoping to get around using FreeRADIUS.

Unfortunately the way EAP-MD5 works with FreeRADIUS is just as bad (or worse) from the 
standpoint of having a file somewhere with all of my users' passwords in them in 
cleartext (or a trivially-decodable) form.

So if I want to use FreeRADIUS and EAP, EAP-TLS is the only option I have left (so 
far).

--J

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