topic Re: NGINX configuration for SSL Inbound Inspection in General Topics

NGINX configuration for SSL Inbound Inspection

grenzi — Tue, 04 May 2021 09:43:06 GMT

Hello everybody,

I'm trying to enable SSL Inbound Inspection to decrypt traffic to an internal webserver that runs on NGINX. I have already added the server certificate and key, and set up the corresponding decryption policy. The problem is that the firewall is not able to decrypt the traffic due to unsupported cipher, so I'm trying to force the NGINX web server to use only the PAN-OS 10 supported cipher suites.

By default, the NGINX server si configured as follows:

ssl_protocols TLSv1.2 TLSv1.3;

ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";

PAN-OS 10 supports the following cipher suites: https://docs.paloaltonetworks.com/compatibility-matrix/supported-cipher-suites/cipher-suites-supported-in-pan-os-10-0/cipher-suites-supported-in-pan-os-10-0-decryption.html#id11638f8b-8bc0-4189-800d-43f1567339b6

anyway I'm not able to select the right combination to make the webserver and the decryption work.

Does anybody have any working NGINX configuration example?

Re: NGINX configuration for SSL Inbound Inspection

reaper — Tue, 04 May 2021 20:50:17 GMT

ECDHE-RSA-AES128-GCM-SHA256 or DHE-RSA-AES128-GCM-SHA256 should work. try removing all the other cyphers as too many could cause conflicts that have one side give up before they can reach a desirable pair

Re: NGINX configuration for SSL Inbound Inspection

grenzi — Mon, 10 May 2021 08:04:49 GMT

@reaper wrote:
ECDHE-RSA-AES128-GCM-SHA256 or DHE-RSA-AES128-GCM-SHA256 should work. try removing all the other cyphers as too many could cause conflicts that have one side give up before they can reach a desirable pair

Unfortunately I get always the same error:

Unsupported cipher. Supported client cipher bitmask: 0x00000000. Supported decrypt profile cipher bitmask: 0x04740614.

I don't know what that "bitmask: 0x00000000" means.