Posts Tagged TLS

Finding the right ciphers with 256 bit alias crypto wars part nine

Finding a good cipher for your web server is not an easy task. openssl ciphers -v ALL:COMPLEMENTOFALL lists all the available ciphers on your system.
What we don’t want

  • SSLv3 that is no longer secure.
  • 128 bit encryption is too weak
  • no encrytion cipther ;)
  • DSS cipher for key auth
  • DHE-RSA-AES256-SHA is no longer secure
  • TLSv1 no longer secure
  • PSK ( pre shared key) cipher
  • CAMELLIA
  • CBC cipher because of the BEAST attack
  • RSA because of FREAK and SMACK and ROBOT
  • Au=None
  • AESCCM it is also a Cipher Block Chaining (CBC)

That gives us:

openssl ciphers -v ALL:COMPLEMENTOFALL | grep -v "SSLv3" | grep -v "(128)" | grep -v "Enc=None" | \
 grep -v "Au=DSS" | grep -v "DHE-RSA-AES256-SHA" | grep -v "TLSv1 " | grep -v "Au=PSK" | grep -v "Kx=RSAPSK" | \
 grep -v "CAMELLIA" | grep -v "CBC" | grep -v "Au=RSA" | grep -v "Au=None" | grep -v "Enc=AESCCM"

now choose your poisen.

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http/2.0 sslciphersuites with 256 bit alias crypto wars part six meeting HIPPA

The chosen SSL Config was very good! But for I client I had to meet the specs from PCI DSS[1], HIPAA[2] and NIST[3].
The server already was PCI DSS ready. However since there are medical data it had to meet HIPAA too.

It turned out that HIPAA does not allow the nice CHACHA20-POLY1305 ciphers and I had to enable SSLStaplingCache that I turned of when I used StartSSL Certs cause of the timeout / outage from the response server from start ssl.

<If "%{SERVER_PORT} == '443'">
    <IfModule mod_headers.c>
        Header always set Strict-Transport-Security "max-age=15553000; preload"
    </IfModule>
</If>
SSLUseStapling On
SSLSessionCache shmcb:/opt/apache2/logs/ssl_gcache_data(512000)
SSLStaplingCache shmcb:/opt/apache2/logs/ssl_stapling_data(512000)
SSLOptions +StrictRequire +StdEnvVars -ExportCertData
SSLProtocol -all +TLSv1.1 +TLSv1.2
SSLCompression Off
SSLHonorCipherOrder On
SSLCipherSuite ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA

SSLOpenSSLConfCmd ECDHParameters secp384r1
SSLOpenSSLConfCmd Curves sect571r1:sect571k1:secp521r1:sect409k1:sect409r1:secp384r1:sect283k1:sect283r1:secp256k1:prime256v1

H2Direct On

I still get an A+ on ssllabs plus all green lights on htbridge ssl test.

[1] Payment Card Industry Data Security Standard
[2] Health Insurance Portability and Accountability Act
[3] National Institute of Standards and Technology

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Apache defend CRIME Attack TLS / SSL

SSL Tests like https://www.ssllabs.com/ssltest/index.html show a vulnerability against CRIME Attack. To overcome / defend that with apache you can turn off the SSL compression.

SSLCompression off

That makes it easy to defend it.

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