Re: Prevent security bypass

[Chris Travers <chris () travelamericas com>]

Adam wrote:

> It depends how secure you want it as a lot of people have said but I would
> personally go for what you suggested as bar the v.expensive suggestions or
> the ones relying on being on the same NT network you arent going to get
> anything very secure. We have a secuirty script called on each secure page.
> The overhead doesnt seem that bad tbh.
>  
What makes you say that?  If you are on NT, then any insecurities of the 
authentication protocol are ALREADY going to affect you.  Applying 
diversity in depth might buy you something but only if it is paired with 
good NT security practices,  Besides, if your server is not secure, you 
are already screwed.

The way I design my web applications which require granularity of 
permissions for different users or other advanced security features is 
based on the following principles:

1)  Primary Security on Backend-- don't try to do any more enforcement 
than you have to on the middleware.  And avoid ANY enforcement of 
anything important on the front-end.  Instead, try to do as much 
enforcement with the backend components as possible and only suppliment 
with the middleware as needed.  The idea here is that you enforce 
permissions using the web server, operating system, and/or information 
store (such as RDBMS and LDAP) as much as possible because these are the 
most robust security-wise, and they can be attacked independently 
anyway.  Furthermore these are the only solutions that can globally 
protect the information (from inside the web context or outside it).

2)  Supplimental Security in Middleware-- Sometimes, it is necessary to 
place information in the information store in an insecure fassion,and 
this could be used for DoS attacks.  One example might be a user profile 
in an RDBMS system where all users will be able to write to and update 
that table.  In this case, enforce additional security on the 
middle-ware.  But this security is much more brittle and not as strong, 
so it should not be relied upon as much.

3)  Protect content In Transport-- Use SSL to protect the content and 
passwords.

Best Wishes,
Chris