Message-ID: <200509010324.j813OlNd008630@web1.megawebservers.com>
Date: Thu, 1 Sep 2005 03:24:47 -0000
From: <liudieyu@...rella.name>
To: <bugtraq@...urityfocus.com>
Subject: Re: secure client-side platform




#1, we are talking about how to do critical secret communication in a secure
way, right? so forget about those putting win9x 24/7 on DSL ... let them
continue contributing to the spam and zombie business ;-)

imagine i'm going to access an e-gold acocunt of $1M ... 
    first i unplug the network cable and remove harddrive;
    then boot with a clean livecd;
    later start firewall and then plug the network cable;
    run "mozilla-firefox about:blank";
    directly go to HTTPS-secured website;
    once done, reboot.
i cannot figure out what could go wrong in the above process ...

clean read-only OS is a solution against "once owned, stay owned" (trojan
stays in system until next format)

it does not solve the problem of the vulnerabilities in client software like
mozilla (as joxean and keith suggested)

if we only have encryption-secured connection to trusted server,
assuming enemy do not have control over the trusted server itself,
our computer can only be compromised if:
     * enemy have total control over the communication channel
       between us and the trusted server
     * AND 
       - there is a vulnerability in the certificate/publickey 
         verification process of client software like mozilla
       - OR the mathematic foundation of publickey-privatekey 
         sign/encrypt trick got a problem.
       - OR we clicked YES in the 
         certificate-is-invalid-continue-or-not dialog
     * AND 
      enemy got vulnerability to exploit after going thru the 
      certificate verification process taken in our side.

chances are rare, hum? the very last sentence of my trooseid article is:
Never touch any not-encryption-secured connection during a
secret-communication op.
you read it, right?

Q: can you really trust Google?
A: it's really up to you which server you choose to store and transfer
encrypted secrets. in my view, the Gmail service of google is just a good
example here ... you got service better than google's gmail, of course go
ahead ... )

honestly, i have not used the tools mentioned in the "why not ... " part
below. it gonna take some time to evaluate those solutions by myself.

####################

"you got a problem"
*** 1 ***
         Joxean Koret <joxeankoret@...oo.es>
 [+] I think this is a bad idea. What about client software vulnerabilities?
You can have a system that were secure but 

currently it's not. 
 [+] Various applications, such as web browsers, mail clients, etc... needs to
be constantly updated to fix the newest 

vulnerabilities.
*** 2 ***
         "Keith Oxenrider" <web10198@...-biotech.com>
 [+] I am sure you will be hearing this from many others, but basically it is
impossible to secure client side computing if 

the client every goes outside of your control (one presumes that if it remains
inside your control you have effective 

controls).  Clearly, server side computing is entirely within the control of
whomsoever owns (or 0wns) the server, so there 

is implicit trust when you connect (can you really trust Google to protect
your content?).
 [+] While your recommendations, if used, will obviously increase the baseline
security of the average person, you can't 

guarentee anything.  Smart card developers run into many of these issues and
they don't have to deal with buggy commodity OSs 

and browsers.  Since the vast majority of users don't even bother to keep
their machines patched (people STILL use Win9x 

connected 24/7 to DSL, btw), offering suggestions on how to make their
computer even more difficult to use is unlikely to win 

any converts.
 [+] Those of us who are already paranoid and have done their homework know
there is no way to ensure on-line security 

besides never doing anything on-line.
 [+] Something to keep in mind, a read-only OS is only as good as its patch
level when it was written and will decay with 

time eventually (soon) reaching an insecure state that can easily be penatrated.


"why not ..."
*** 1 ***
         Joxean Koret <joxeankoret@...oo.es>
Why not use a system like LTSP (Linux Terminal Server Project) or any other
"Think Client" based system?
*** 2 ***
         "Beauford, Jason" <jbeauford@...htInOnePet.com>
Tinfoil Hat linux ..silly.  http://tinfoilhat.shmoo.com/
*** 3 ***
         "Gustavo Paredes" <gustavo.paredes@...ernet-solutions.com.co>
Do you know secuware? www.secuware.com

####################

how to have a secure client-side platform for secret communication?
    ... transferring and storing secret messages, online banking, etc

i got some fresh ideas in mind, and would like to share it here:
0. watch network with sniffer, so be sure no byte is sent to weird destinations
1. read-only operating system(knoppix, etc), so every boot is a fresh start
2. get every secret processed in memory and stored as encrypted in remote server

any suggesion or fresh idea on this topic is welcome

this document for ordinary people on the street:
http://umbrella.name/upid/trooseid

bugtraq guys can directly go to the conclusion part:
http://umbrella.name/computer/trooseid/trooseid_online/#conclusion

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