Large Varying IP Pools for DNS (CB Defense dev-prod05.conferdeploy.net) And Firewall Rules[SOLUTION]

Reply
BrianRa
L3 Networker


@vsys_remo wrote: 

 So if the client uses this name but connects to an IP that is controlled by an attacked, the firewall will happily allow the connection with the rule in your screenshot.


As soon as I realized how that worked this was my first thought!

Fortunately our DNS is fairly secure (externally anyway).  However if a bad actor got in and started spoofing DNS internally then yes we would have problems.  Also a user that understands the vulnerability would be able to access sites that are blocked.  We do have all of the Security Profiles built and are using all but Data Filtering on this rule.

 

Unfortunately I don't know that DNS proxy would work internally as we are using split DNS internally for both domain and some site requests.  During our initial configuration Palo Alto implied this was not prefered due to the load it put on the firewall (this may not be correct but it has caused us to avoid it on most of our networks).

“Do not own a computer;
Do not power it on;
and do not use one.”

Morris’s Three Golden Rules of Computer Security

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