05-05-2019 05:20 PM
Dear all,
I am using PA-8.0.0-ESXi virtual machine and I am trying to prevent covert channel communication using ICMP Payload.
For example, as captured using Wireshark, the default ICMP type 8 (Echo request) for Windows machine is abcdefghijklmnopqrstuvwabcdefghi or \x 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 61 62 63 64 65 66 67 68 69 x\ in hexadecimal. I only want to allow ICMP packet that has a specific payload pattern to go through the firewall. Therefore, other ICMP packet that has random payload value will be blocked.
Is there any way to do that on Palo Alto Firewall? I have tried to define custom applications with signature but I cannot get it working. I think I am missing something.
Any help would be appreciated.
Thank you,
Sincerely,
Bagus Hanindhito
