[standards-jig] Re: [Foundation] Last Minute JEP 78 Concerns

Ralph Siemsen ralphs at blueairnetworks.com
Tue May 27 22:06:23 UTC 2003


Dave Smith wrote:

> digest auth == SHA1(stream id + password-plaintext)
> 
> edigest auth == SHA1(stream id + SHA1(password-plaintext))
> 
> This would mean that one never sends the plaintext password over the 
> wire, even for registration.

That is true.  But you are sending only a variation with no challenge 
posed from the server.  So, anyone with a packet sniffer can capture the 
  SHA1(password-plaintext) as it is transmitted.  This includes your 
friendly sysadmin who you wish you could trust.  The sniffed hashed 
password is all it takes for another client to duplicate the same 
connection - they do not need to know the original password.

So, as was pointed earlier, the effect of hashing the password is no 
different than sending the plain password.  It is just a different 
string being sent around.  Anyone can see this string, either by 
sniffing the traffic or by looking at the spool file.  And then they can 
login.

So, you have to weigh the efforts of changing all the clients against 
this supposed "increase" in security that in fact is exactly the same as 
what we have with digest right now.

The issue of the password being sniffed cannot be fixed, wether it is 
encrypted or not, without the use of something like SSL or SASL, and 
that requires client changes - which will take time to implement and 
adopt over the millions of users.

So focus on the other problem - that of the password being stored 
plaintext on the server.  There are a variety of ways to avoid that, all 
of which do not require any changes to the clients to implement, and 
will not break any existing clients.

-R




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