RE: Client/Server application that does not authenticate users

From: Dinis Cruz (
Date: 08/14/04

  • Next message: Dinis Cruz: "RE: Client/Server application that does not authenticate users"
    To: "'Brian Erdelyi'" <>, <>
    Date: Sat, 14 Aug 2004 00:29:08 +0100

    I knew of an web app that got the username for the user variable "Username"

    Guess what would happen in you typed in the client workstation "Set
    Username=Admin" :)

    For guidelines check out the OWASP documents: Top 10
    (, Testing guide
    (, the ISO 17799 Project
    ( and the app sec FAQ

    Hope this helps

    Best regards

    Dinis Cruz
    .Net Security Consultant

    > -----Original Message-----
    > From: Brian Erdelyi []
    > Sent: 13 August 2004 11:58
    > To: Dinis Cruz;
    > Subject: RE: Client/Server application that does not authenticate users
    > I am working with the vendor on this. Unfortunately,
    > I was assured by the cendor that the application does
    > authenticate users and uses accesscontrol lists to
    > assign permissions. They claimed I was was using an
    > uncommon interpretation of the term "authentication".
    > The next level of support disagreed with my use of the
    > term "vulnerability".
    > The server does ask for a username (the client
    > automatically forwards the Windows username of the
    > currently logged on computer) but no password is
    > requested or sent at any point. This is by design of
    > the application (which from my perspective is
    > seriously flawed for an application that allows users
    > to sell and trade millions of dollars worth of bonds).
    > I will give the vendor some time to analyse the
    > description I have provided to them and respond.
    > I'd like to provide some very specific suggestions and
    > guidance on how other applications are designed and
    > coded to authenticate users.
    > Is there an RFC on secure programming?
    > --- Dinis Cruz <> wrote:
    > > Quite common.
    > >
    > > The other major mistake that most do is to rely on
    > > the Client's GUI to
    > > enforce the 'security boundaries' of the client
    > > application (for example:
    > > they rely on the fact that the user's GUI doesn't
    > > have the functionality to
    > > change passwords (including the administrators), so
    > > if such a request is
    > > made it must be from a valid source....)
    > >
    > > But, the big question is: "what happens next?"
    > >
    > > Are they going to tell their customers that their
    > > data could had been (or
    > > was) compromised?
    > >
    > > Dinis Cruz
    > > .Net Security Consultant
    > > DDPlus
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Mail is new and improved - Check it out!

  • Next message: Dinis Cruz: "RE: Client/Server application that does not authenticate users"

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