topic Which weak cipher suites for SSL/TLS to delete in General Topics

Which weak cipher suites for SSL/TLS to delete

PaulBrock — Mon, 22 May 2023 03:24:49 GMT

Hi All,

I recently had a pen test return the following results:

TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (`0xc030`) ECDH secp256r1 (eq. 3072 bits RSA) FS	256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (`0xc02f`) ECDH secp256r1 (eq. 3072 bits RSA) FS	128
TLS_RSA_WITH_AES_256_GCM_SHA384 (`0x9d`) WEAK	256
TLS_RSA_WITH_AES_128_GCM_SHA256 (`0x9c`) WEAK	128
TLS_RSA_WITH_AES_256_CBC_SHA256 (`0x3d`) WEAK	256
TLS_RSA_WITH_AES_128_CBC_SHA256 (`0x3c`) WEAK	128
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (`0x9f`) DH 2048 bits FS	256
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 (`0x9e`) DH 2048 bits FS	128
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (`0xc014`) ECDH secp256r1 (eq. 3072 bits RSA) FS WEAK	256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (`0xc013`) ECDH secp256r1 (eq. 3072 bits RSA) FS WEAK	128
TLS_RSA_WITH_AES_128_CBC_SHA (`0x2f`) WEAK	128
TLS_DHE_RSA_WITH_AES_256_CBC_SHA (`0x39`) DH 2048 bits FS WEAK	256
TLS_DHE_RSA_WITH_AES_128_CBC_SHA (`0x33`) DH 2048 bits FS WEAK	12

which of the below cipher suites do I disable to comply ? (enc-algo-3des is already disabled), this is set on my global protect interface, will anything break 🙂

+ auth-algo-sha1         Allow authentication SHA1
+ auth-algo-sha256       Allow authentication SHA256
+ auth-algo-sha384       Allow authentication SHA384
+ enc-algo-3des          Allow algorithm 3DES
+ enc-algo-aes-128-cbc   Allow algorithm AES-128-CBC
+ enc-algo-aes-128-gcm   Allow algorithm AES-128-GCM
+ enc-algo-aes-256-cbc   Allow algorithm AES-256-CBC
+ enc-algo-aes-256-gcm   Allow algorithm AES-256-GCM
+ enc-algo-rc4           Allow algorithm RC4
+ keyxchg-algo-dhe       Allow algorithm DHE
+ keyxchg-algo-ecdhe     Allow algorithm ECDHE
+ keyxchg-algo-rsa       Allow algorithm RSA
+ max-version            max-version
+ min-version            min-version

Re: Which weak cipher suites for SSL/TLS to delete

Raido_Rattameister — Mon, 22 May 2023 12:38:46 GMT

I assume you refer to GlobalProtect ciphers.

To get A- score in SSLLabs test run following 4 commands (adjust template and profile name to match your environment)

If config is managed inside firewall

set shared ssl-tls-service-profile GlobalProtect protocol-settings auth-algo-sha1 no
set shared ssl-tls-service-profile GlobalProtect protocol-settings enc-algo-3des no
set shared ssl-tls-service-profile GlobalProtect protocol-settings enc-algo-rc4 no
set shared ssl-tls-service-profile GlobalProtect protocol-settings keyxchg-algo-rsa no

If config is pushed from Panorama
set template Template-name config shared ssl-tls-service-profile GlobalProtect protocol-settings auth-algo-sha1 no
set template Template-name config shared ssl-tls-service-profile GlobalProtect protocol-settings enc-algo-3des no
set template Template-name config shared ssl-tls-service-profile GlobalProtect protocol-settings enc-algo-rc4 no
set template Template-name config shared ssl-tls-service-profile GlobalProtect protocol-settings keyxchg-algo-rsa no

Re: Which weak cipher suites for SSL/TLS to delete

BPry — Mon, 22 May 2023 12:40:36 GMT

@PaulBrock,

I'd really suggest running through this on a non-production portal/gateway before actually making this change on your production portal/gateway ssl-tls-service-profile. While disabling weaker protocol settings generally doesn't cause any issues, I've also run into some very odd client configuration settings that would have broken things had we not tested it prior to making the change.

set shared ssl-tls-service-profile GlobalProtect protocol-settings keyxchg-algo-rsa no set shared ssl-tls-service-profile GlobalProtect protocol-settings auth-algo-sha1 no

Replace "GlobalProtect" with whatever profile you're using.

Re: Which weak cipher suites for SSL/TLS to delete

PaulBrock — Tue, 23 May 2023 02:47:31 GMT

Thank you so much, this is so helpful 👍

I wish that when I contacted support, rather than sending KBs they would simply answer like you have.

Re: Which weak cipher suites for SSL/TLS to delete

Han.Valk — Tue, 23 May 2023 16:49:56 GMT

I would recommend the following settings as these will get you an A- on SSL Labs:

set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings auth-algo-sha1 no
set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings enc-algo-3des no
set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings enc-algo-rc4 no
set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings enc-algo-aes-128-cbc no
set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings enc-algo-aes-256-cbc no
set shared ssl-tls-service-profile <SSL/TLS service profile name> protocol-settings keyxchg-algo-rsa no

It is very unfortunate that Palo Alto will not fix secure renegotiation as that would get you an A+.

Also sendig the root certificate should be fixed by Palo Alto.

Re: Which weak cipher suites for SSL/TLS to delete

PaulBrock — Tue, 23 May 2023 22:10:12 GMT

Hi Han,

You must have received the same report,😀

the Pen testers flagged Weak ciphers, secure renegotiation, and also Information Disclosure

With regard to Information disclosure:

I don't suppose anyone knows how to turn off Palo Alto "Palo Alto GlobalProtect Gateway httpd"

Re: Which weak cipher suites for SSL/TLS to delete

Raido_Rattameister — Wed, 24 May 2023 02:15:45 GMT

Why would you want to turn off gateway access over https?

It is needed for gateway functionality.

GlobalProtect agent will try 3 times to connect over udp/4501 to establish IPSec tunnel but if it fails then it will fail back to SSL-VPN over tcp/443 (those are default ports numbers that can be changed).

Re: Which weak cipher suites for SSL/TLS to delete

PaulBrock — Wed, 24 May 2023 02:26:13 GMT

Hi Raido,

sorry, I probably did not explain myself properly.

I need to turn off Palo Alto disclosing information to a public scan.

at the moment you can see the following information "Palo Alto GlobalProtect Gateway httpd"