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Re: SimplePAMApps-0.50

I don't mean to offend anyone, but...

Call me crazy, but you're trading the risk of someone sniffing for the
risk of someone reading the file .passwd and getting a password which
you'll now be guaranteeing to be both their netatalk and system passwords?
Sounds like a net loss to me... I don't know what sort of physical network
you have, but at least in the places I've worked, I've felt more confident
that I could keep track of what devices were being plugged into my hubs
than protect my users from doing something that would display the contents
of an arbitrary file of theirs to the world. Especially if you have ANY
other non-crypto protocols on the wire already. Do any of these mac users
have email by any chance? Cleartext pop-3 or imap?

Also, from what I remember about afp, it's "2 way scrambled" which I
suspect isn't exactly strong crypto. If a 3rd party could easily reverse
the scramble then you really gain nothing to offset having to keep
cleartext passwords.

One of the nice things about AFP is that, afaik, the way you authenticate
can be extended by the server for a vanilla client. The NT afp
implementation (the last time I saw it was on 3.51, I don't work near NT
anymore) had a volume that it shared to the client that had something to
do with MS authentication. While I don't suggest this is anywhere near as
easy as hacking passwd.c as you describe, I think perhaps a properly
motived couple of geeks who knew what they were doing should be able to
come up with a netatalk specific authentication method that relied onthe
system password and didn't use cleartext.

Sorry if the security advice was unwanted...


On Tue, 13 Apr 1999, Alex Yu wrote:

> SimplePAMApps-0.50
> Hello,
> I am trying to hack passwd.c so that when users use it to change their
> password, passwd will also update netatalk (AppleTalk) password.  netatalk
> does support PAM if I choose to use clear text as password auth, but
> because there is always a chance that people will sniff my subnet, so I
> decided to use 2-way encrypted auth instead of clear text auth.  2-way
> encrypted does not read /etc/passwd, instead of that, users need to have a
> .passwd in their home directory.  .passwd must has clear text string
> without character return key.
> For example, if your password is a123456B, then .passwd must has a123456B
> as clear text.  Users hate to have 2 or more passwords on a same system.
> So which I want to do is when users use passwd to change their password,
> passwd will also update the netatalk passwd.
> I know C++, but do not know C.  So I wonder if you can give a help on
> this?  (I use cout, cin, ifstream... etc.  I have no idea how printf,
> fprintf works.)
> Best Regards,
> Alex Yu

"[T]hey said something to the effect that Linux has 'the tendency not to 
crash.' ... It's like me listing 'the tendency not to murder people' as one of
my good character traits. :-> It seems that people have grown so accustomed to
buggy OS's that when Linux simply does what it's supposed to do, it comes 
across as something new and different." Scott Webster on linux-biz 20 Feb 1999

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