New PCI SSLCipherSuite requirements

General Discussion
1

I just finished a long conference call with my PCI compliant provider and VISA.

After testing on several servers I found some weakness in the current SSLCipherSuite in both webmin and usermin plus normal SSL sites.

The following information came from testing at https://www.ssllabs.com/ssldb/ and info from http://blog.ivanristic.com/2011/10/mitigating-the-beast-attack-on-tls.html

The Cipher’s that both my PCI provider and I came up with that will be the best security for any SSL attacks is…

ECDHE-RSA-AES256-SHA384:AES256-SHA256:RC4:HIGH:!MD5:!SSLv2:!SSLv3:!ADH:!aNULL:!eNULL:!NULL:!DH:!ADH:!EDH:!AESGCM

For apache these lines are now required by my PCI provider and other providers will be contacted to update their requirements in a few days.

SSLHonorCipherOrder On SSLCipherSuite ECDHE-RSA-AES256-SHA384:AES256-SHA256:RC4:HIGH:!MD5:!SSLv2:!SSLv3:!ADH:!aNULL:!eNULL:!NULL:!DH:!ADH:!EDH:!AESGCM

Both Webmin and Usermin must be updated to use those Cipher’s in that order to maintain PCI compliance.

I will be updating my PCI docs to include the new settings that will be required.

If anyone has questions you can contact me directly via email (sgrayban[at]gmail.com) or via phone +1.509.279.0285

2

Using this for SSLCipherSuite worked for me with OpenSSL version 0.9.8 but didn’t work with 0.9.7 to mitigate the BEAST.

openssl ciphers -v 'ECDHE-RSA-AES256-SHA384:AES256-SHA256:AES256-SHA256:RC4:HIGH:!MD5:!SSLv2:!ADH:!aNULL:!eNULL:!NULL:!DH:!ADH:!EDH:!AESGCM'

Between OpenSSL version the cipher suites will be same except for the following:

0.9.7 has:

EXP1024-RC4-SHA SSLv3 Kx=RSA(1024) Au=RSA Enc=RC4(56) Mac=SHA1 export

where 0.9.8 doesn’t

and 0.9.8 has:

AES128-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(128) Mac=SHA1

where 0.9.7 doesn’t.

Not 100% sure it’s the OpenSSL version creating the difference. My two servers are running CentOS 4.x and 5.x. So, they’re generally similar but not identical.

3

@sgrayban

Two questions:

  1. Why do you repeat AES256-SHA256 twice in your config statement?
  2. Why do you disallow AESGCM?
4

I had exactly the same questions @hudibu!

I found this list is now installed by Virtualmin when installed on Debian, but those two entries make little sense to me. What am I missing?

5

It was a typo

6

To prevent the beast and poodle attacks in webmin/usermin the following cypher list is now required…

https://www.borgnet.net/cypher.txt <-- this will give you exactly what you need to add or change to your miniserv.conf files

ssl=1 ssl_redirect=1 ssl_version=10 ssl_cipher_list=ECDHE-RSA-AES256-SHA384:AES256-SHA256:RC4:HIGH:MEDIUM:+TLSv1:+TLSv1.1:+TLSv1.2:!MD5:!ADH:!aNULL:!eNULL:!NULL:!DH:!ADH:!EDH:!AESGCM no_sslcompression= ssl_honorcipherorder=0