DMZ

["Daniel Salenger" <dsalenger @ dttus . com>]

     I am working with a client that has the following configuration:
     
     
     {Internet}--[ISP]--[Firewall-1]-[WWW server]-[router]--[internal net]
     
     Due to prior conversations and observations from this list, I consider 
     WWW servers to be less than secure.  Though I promote the 
     Dual-Firewall DMZ approach, I am uncertain about the dependence that 
     my client may be placing on the router (as a second firewall) in this 
     diagram.
     
     To add detail:
     - The primary firewall will allow HTTP, HTTPS, and SMTP inbound
     - Only HTTP and HTTPs will be allowed to the web server from the 
     Internet.
     
     My train of thought is that if the WWW server is compromised 
     (Firewall-1 does not seem to look at the 'insides' of the HTTP packet 
     traffic to look for harmful commands and buffer overflows, etc...) 
     then an attacker would have a launching point for the next phase of 
     the attack which would be against the router.  Any thoughts or 
     opinions concerning this situation?  Thank you for any assistance.
     
     Dan Salenger
     Deloitte & Touche LLP
     dsalenger @
 dttus .
 com