TLS policy vs PCI compliance

paul_marwick · June 11, 2019, 7:23am

From the scan report on the system that I’m trying to find a fix for, 1.2 is much preferred. There are also some protocols that are out of favour - I’m not sure how critical it is, but several of the Diffie-Hellman protocols are regarded as weak.

pike · June 11, 2019, 11:29am

@paul_marwick would you be please be explicit of what Diffie-Hellman protocols are marked as weak?

stephdl · June 11, 2019, 7:51pm

I would be curious on your thoughts against the http-admin, we have hardened the server-manager service but we still allow TLS1.0 and TLS1.1

 Has server cipher order?     yes (OK)
 Negotiated protocol          TLSv1.2
 Negotiated cipher            DHE-RSA-AES256-GCM-SHA384, 2048 bit DH
 Cipher order
    TLSv1:     DHE-RSA-AES256-SHA ECDHE-RSA-AES256-SHA 
    TLSv1.1:   DHE-RSA-AES256-SHA ECDHE-RSA-AES256-SHA 
    TLSv1.2:   DHE-RSA-AES256-GCM-SHA384 DHE-RSA-AES256-SHA256 DHE-RSA-AES256-SHA
               ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-SHA384
               ECDHE-RSA-AES256-SHA

you can use testssl to check it https://wiki.nethserver.org/doku.php?id=testing_tls_ssl_encryption&s[]=tls#testsslsh

all tests are welcome, changing ciphers or protocols could drive to issues and each service is different so we could not copy and paste the same configuration

bwdjames · June 12, 2019, 8:18am

Thanks for that information @stephdl, that is helpful to know.

Personally my view is that TLSv1.0 should be disabled by default and if someone still requires it, they could then enable it. That is the better from a security point of view.

paul_marwick · June 12, 2019, 1:05pm

I’m still going through the failure report from Security Metrics (firm that did the compliance testing). In it they say this:

At least one of the services on the remote host supports a Diffie-Hellman
key exchange using a public modulus smaller than 2048 bits. Diffie-
Hellman key exchanges with keys smaller than 2048 bits do not meet
the PCI definition of strong cryptography as specified by NIST Special
Publication 800-57 Part 1.

They also indicate a preference for not using ciphers which use 3DES encryption.

If it is of any interest to people, I have a copy of the Security Metrics 2019 Guide to PCI_DSS compliance. It covers all aspects of making systems secure, including things like data encryption for card data. I can put it up on Google Drive and post a URL if anyone is interested.

paul_marwick · June 12, 2019, 1:09pm

No complaints here. I’m glad it has attracted interest. I’ve already been impressed with how much better Nethserver is at handling spam and attempted virus dumps. If a new security policy can be provided that allows me to disable TLS1 and TLS1.1, that will make it that much more useful to me…

paul_marwick · June 12, 2019, 1:12pm

I think that would be very useful. I was able to use a db setting in SME to turn off TLSv1.0 support, and did so on all the SME systems I support quite a long time ago.

stephdl · June 12, 2019, 4:43pm

sorry if I misunderstood your issue, do you know how to modify the tls protocol to fit your need, remove the tls1.0 & tls1.1 is easy, after you need to test with testssl

check etc/e-smith/templates/etc/httpd/conf.d/nethserver.conf/10tls_policy_20180621

paul_marwick · June 12, 2019, 8:04pm

Thanks for that. I’ll have a look and do some more reading of the dev docs. I would very much like to see an upgraded TLS policy to turn off TLSv1 and TLSv1.1 - that in itself would get me most of what I need. I’m not sure whether further modifications to the accepted encryption policies would be needed at that point.

I’ve done some scans using sslscan, and I’m now looking at testssl.sh as well.

stephdl · June 12, 2019, 8:47pm

Will try to do some tests tomorrow but we have the book

https://bettercrypto.org/

This is the stronger recommended

https://bettercrypto.org/#_configuration_a_strong_ciphers_fewer_clients

stephdl · June 13, 2019, 4:09pm

if you want to only remove tls1.0 and tls1.1
in etc/e-smith/templates/etc/httpd/conf.d/nethserver.conf/10tls_policy_20180621

-SSLProtocol all -SSLv2 -SSLv3 
+SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1

then restart httpd

it seems that quite all clients could connect

Android 4.4.2	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Android 5.0.0	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 DH 2048 FS
Android 6.0	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 DH 2048 FS
Android 7.0	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
BingPreview Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Chrome 49 / XP SP3	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ECDH secp256r1 FS
Chrome 69 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Chrome 70 / Win 10	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Firefox 31.3.0 ESR / Win 7	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ECDH secp256r1 FS
Firefox 47 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ECDH secp256r1 FS
Firefox 49 / XP SP3	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Firefox 62 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Googlebot Feb 2018	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
IE 11 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win 8.1 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win Phone 8.1 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 ECDH secp256r1 FS
IE 11 / Win Phone 8.1 Update R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Edge 15 / Win 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Edge 13 / Win Phone 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Java 8u161	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
OpenSSL 1.0.1l R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
OpenSSL 1.0.2e R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Safari 6 / iOS 6.0.1	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 7 / iOS 7.1 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 7 / OS X 10.9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 8 / iOS 8.4 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 8 / OS X 10.10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 9 / iOS 9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 9 / OS X 10.11 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 10 / iOS 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 10 / OS X 10.12 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Apple ATS 9 / iOS 9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Yahoo Slurp Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
YandexBot Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS

if you follow the strong cipher configuration

in etc/e-smith/templates/etc/httpd/conf.d/nethserver.conf/10tls_policy_20180621

-SSLProtocol all -SSLv2 -SSLv3 
+SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1

+SSLCipherSuite  EDH+aRSA+AES256:EECDH+aRSA+AES256:!SSLv3

remove the cipher list then restart httpd

in that case you restrict the numbers of client

Android 4.4.2	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Android 5.0.0	Server sent fatal alert: handshake_failure
Android 6.0	Server sent fatal alert: handshake_failure
Android 7.0	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
BingPreview Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Chrome 49 / XP SP3	Server sent fatal alert: handshake_failure
Chrome 69 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Chrome 70 / Win 10	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Firefox 31.3.0 ESR / Win 7	Server sent fatal alert: handshake_failure
Firefox 47 / Win 7 R	Server sent fatal alert: handshake_failure
Firefox 49 / XP SP3	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Firefox 62 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Googlebot Feb 2018	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
IE 11 / Win 7 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win 8.1 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win Phone 8.1 R	Server sent fatal alert: handshake_failure
IE 11 / Win Phone 8.1 Update R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
IE 11 / Win 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Edge 15 / Win 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Edge 13 / Win Phone 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Java 8u161	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
OpenSSL 1.0.1l R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
OpenSSL 1.0.2e R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
Safari 6 / iOS 6.0.1	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 7 / iOS 7.1 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 7 / OS X 10.9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 8 / iOS 8.4 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 8 / OS X 10.10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 DH 2048 FS
Safari 9 / iOS 9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 9 / OS X 10.11 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 10 / iOS 10 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Safari 10 / OS X 10.12 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Apple ATS 9 / iOS 9 R	RSA 2048 (SHA256)	TLS 1.2	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ECDH secp256r1 FS
Yahoo Slurp Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS
YandexBot Jan 2015	RSA 2048 (SHA256)	TLS 1.2	TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH 2048 FS

stephdl · June 13, 2019, 6:46pm

reading this http://docs.nethserver.org/en/latest/tlspolicy.html#tlspolicy-section we could release a TLS policy and get rid of TLS1.x for apache…of course keep 1.2

I am not sure we could be PCI compliant, I assume it is the work of the sysadmin for this purpose, he is paid for this but we could help

cc @davidep

paul_marwick · June 13, 2019, 9:05pm

stephdl:

if you follow the strong cipher configuration

in etc/e-smith/templates/etc/httpd/conf.d/nethserver.conf/10tls_policy_20180621
-SSLProtocol all -SSLv2 -SSLv3 
+SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1

+SSLCipherSuite  EDH+aRSA+AES256:EECDH+aRSA+AES256:!SSLv3
remove the cipher list then restart httpd

in that case you restrict the numbers of client

That sounds like what is needed for any system that needs to meet the PCI-DSS standard. One thing I don’t follow though - does this affect all open ports, or only the HTTP, HTTPS ports?

davidep · June 13, 2019, 9:18pm

I’d like to see this new TLS policy as the default of NethServer 7.7

Only https; we have to configure (and test) other daemons as well…

pike · June 14, 2019, 9:14am

I’d like to see the new policy as an option soon on 7.6.

davidep · June 14, 2019, 11:05am

So far we talked about service configuration. Does the PCI specs require the same on clients?

As suggested by @giacomo, we must care the Postfix SMTP client config too. It talks to other MTAs, and they could support only TLS 1.0… what does PCI say here?

stephdl · June 14, 2019, 11:59am

We have removed tls1. 0 for ejaberd iirc

stephdl · June 14, 2019, 1:50pm

does it won’t be an issue for us if old clients could not connect ?

IE 11 / Win Phone 8.1 R Server sent fatal alert: handshake_failure

Firefox 31.3.0 ESR / Win 7	Server sent fatal alert: handshake_failure
Firefox 47 / Win 7 R	Server sent fatal alert: handshake_failure

Chrome 49 / XP SP3 Server sent fatal alert: handshake_failure

Android 5.0.0	Server sent fatal alert: handshake_failure
Android 6.0	Server sent fatal alert: handshake_failure

we need to take care about also elliptic curve certificate

@nrauso, do you think that if we decide to block the client list above, this could drive to increase the ticket of your customers

stephdl · June 14, 2019, 1:57pm

FYI

ejabberd /etc/ejabberd/ejabberd.yml

TLS policy 20181001

define_macro:
‘CERTFILE’: “/etc/ejabberd/ejabberd.pem”
‘TLSOPTS’:
- “no_sslv3”
- “no_tlsv1”
- “cipher_server_preference”
‘CIPHERS’: “ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:
ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:
ECDHE-ECDSA-AES128-SHA256:EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:
EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH:+CAMELLIA256:+AES256:
+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:
!PSK:!DSS:!RC4:!SEED:CAMELLIA256-SHA:AES256-SHA:CAMELLIA128-SHA:AES128-SHA”
dovecot /etc/dovecot/dovecot.conf

TLS

cipher selection 2018-06-21 (RSA and ECC certificate)

ssl_dh_parameters_length = 2048

ssl_protocols = !SSLv3 !SSLv2

ssl_cipher_list = ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH:+CAMELLIA256:+AES256:+CAMELLIA128:+AES128:+SSLv3:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:CAMELLIA256-SHA:AES256-SHA:CAMELLIA128-SHA:AES128-SHA

ssl_prefer_server_ciphers = yes
postfix /etc/postfix/main.cf

TLS

cipher selection 2018-06-21 (RSA and ECC certificate)

smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
smtpd_tls_protocols = !SSLv2, !SSLv3
smtpd_tls_mandatory_ciphers=high
tls_high_cipherlist=ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:EDH+CAMELLIA:EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA256:EECDH:+CAMELLIA128:+AES128:+SSLv3:kEDH:CAMELLIA128-SHA:AES128-SHA
smtpd_tls_exclude_ciphers=aNULL:eNULL:LOW:3DES:MD5:EXP:PSK:DSS:RC4:SEED:IDEA

tls_preempt_cipherlist = yes
nethgui /etc/httpd/admin-conf/httpd.conf

Cipher selection 2018-06-21

Only TLS1.2 cipher (RSA and ECC certificate)

SSLCipherSuite EDH+aRSA+AES256:EECDH+aRSA+AES256:ECDHE-ECDSA-AES256-GCM-SHA384:
ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:
ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256

SSLProtocol All -SSLv2 -SSLv3

SSLHonorCipherOrder On
SSLCompression off
SSLUseStapling on
SSLStaplingCache “shmcb:logs/stapling-cache(150000)”

stephdl · June 14, 2019, 2:13pm

https://www.linuxquestions.org/questions/linux-server-73/disabling-tlsv1-0-on-postfix-%3D-~25-of-mails-not-received-4175572056/

in 2016, 25% of email not received when tls1.0 removed

TLS policy vs PCI compliance

TLS policy 20181001

TLS

cipher selection 2018-06-21 (RSA and ECC certificate)

TLS

cipher selection 2018-06-21 (RSA and ECC certificate)

Cipher selection 2018-06-21

Only TLS1.2 cipher (RSA and ECC certificate)