Enable additional ciphers

[lorenze]

Hi Folks,

I'm fairly new to F5 and was wondering if we can add additional ciphers to through our ssl profiles. Currently we have Big-IP 11.5.4 and for client and server ssl profile we have this set for the ciphers:DEFAULT:!SSLv2:!EXPORT:RSA+AES:RSA+3DES:RSA+RC4:ECDHE+AES:ECDHE+3DES:ECDHE+RC4:!MD5:!SSLv3 . I went to SSLlabs and try to scan our website and it gives me this ciphers:

# TLS 1.2 (suites in server-preferred order)
TLS_RSA_WITH_AES_256_CBC_SHA256 (0x3d)  WEAK256TLS_RSA_WITH_AES_256_CBC_SHA (0x35)  WEAK256TLS_RSA_WITH_AES_128_CBC_SHA256 (0x3c)  WEAK128TLS_RSA_WITH_AES_128_CBC_SHA (0x2f)  WEAK128TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa)  WEAK112TLS_RSA_WITH_RC4_128_SHA (0x5)  INSECURE128TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (0xc028)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK256TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK256TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (0xc027)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK128TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK128TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA (0xc012)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK112
# TLS 1.1 (suites in server-preferred order)
TLS_RSA_WITH_AES_256_CBC_SHA (0x35)  WEAK256TLS_RSA_WITH_AES_128_CBC_SHA (0x2f)  WEAK128TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa)  WEAK112TLS_RSA_WITH_RC4_128_SHA (0x5)  INSECURE128TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK256TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK128TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA (0xc012)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK112
# TLS 1.0 (suites in server-preferred order)
TLS_RSA_WITH_AES_256_CBC_SHA (0x35)  WEAK256TLS_RSA_WITH_AES_128_CBC_SHA (0x2f)  WEAK128TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa)  WEAK112TLS_RSA_WITH_RC4_128_SHA (0x5)  INSECURE128TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK256TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK128TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA (0xc012)  ECDH secp256r1 (eq. 3072 bits RSA)   FS   WEAK112

I was hoping to find a way if possible to add this newer ciphers through the SSL profile.

TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (0xc02c)   ECDH x25519 (eq. 3072 bits RSA)   FS256TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (0xcca9)   ECDH x25519 (eq. 3072 bits RSA)   FS256TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8 (0xc0af)   ECDH x25519 (eq. 3072 bits RSA)   FS256TLS_ECDHE_ECDSA_WITH_AES_256_CCM (0xc0ad)   ECDH x25519 (eq. 3072 bits RSA)   FS256TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384 (0xc05d)   ECDH x25519 (eq. 3072 bits RSA)   FS256TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (0xc02b)   ECDH x25519 (eq. 3072 bits RSA)   FS128TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 (0xc0ae)   ECDH x25519 (eq. 3072 bits RSA)   FS128TLS_ECDHE_ECDSA_WITH_AES_128_CCM (0xc0ac)   ECDH x25519 (eq. 3072 bits RSA)   FS128TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256 (0xc05c)   ECDH x25519 (eq. 3072 bits RSA)   FS128

Is this something that can be done through F5? I hope someone can share their expertise.

Best,

[Dario_Garrido]

Hello Lorenze.

Those ciphers should already be included in the Native suite for 11.5.4

REF - https://support.f5.com/csp/article/K13163#11.5.3

Check with this command:

tmm --clientciphers DEFAULT

Here you have an example of how to include 'ECDHE_ECDSA' on your SSL profile.

REF - https://support.f5.com/csp/article/K13171#sslcipher

Regards,

Dario.

[lorenze]

Hello  ,

Thank you for your response. I will try to update the cipher string on my client ssl profile to this one:

DEFAULT:!SSLv2:!EXPORT:RSA+AES:RSA+3DES:RSA+RC4:ECDHE+AES:ECDHE+3DES:ECDHE+RC4:ECDHE+ECDSA:ECDHE+AES-GCM:!MD5:!SSLv3

and see if that gives me the cipher that we need. I'll update here on how it goes.

Thanks!

[lorenze]

So I tried updating our client ssl profile and specified this value on the cipher and did a scan on ssllabs but its not showing the ECDHE-ECDSA ciphers. Am I missing something?

DEFAULT:!SSLv2:!EXPORT:RSA+AES:RSA+3DES:RSA+RC4:ECDHE+AES:ECDHE+3DES:ECDHE+RC4:ECDHE_ECDSA:ECDHE+AES-GCM:!MD5:!SSLv3

[Dario_Garrido]

Hello Lorenze.

Put this in your CLI:

tmm --clientciphers DEFAULT:!SSLv2:!EXPORT:RSA+AES:RSA+3DES:RSA+RC4:ECDHE+AES:ECDHE+3DES:ECDHE+RC4:ECDHE_ECDSA:ECDHE+AES-GCM:!MD5:!SSLv3

If this output shows 'ECDHE-ECDSA' ciphers, then those should be included during TLS handshake.

To validate this, take a traffic capture during those tests and check the TLS client hello to see if those ciphers are included during negotiation.

Regards,

Dario.

[Dario_Garrido]

Hello Lorenze.

There are some bugs regarding this kind of cipher suites.

https://cdn.f5.com/product/bugtracker/ID510837.html

https://cdn.f5.com/product/bugtracker/ID435055.html

https://cdn.f5.com/product/bugtracker/ID503620.html

https://cdn.f5.com/product/bugtracker/ID529400.html

I guess you could be matching some of them.

Regards,

Dario.

[lorenze]

Hi  ,

Thank you for your response. It could be a bug as mentioned, I hope there is another workaround to enable any of the TLS_ECDHE_ECDSA** ciphers as this is also one of your clients cipher requirement. Appreciate your response.

Thanks,

[Dario_Garrido]

Hello Lorenze.

To confirm you are facing a bug, you can configure your client SSL profile to use only 'ECDHE_ECDSA' ciphers.

# tmm --clientciphers ECDHE_ECDSA
       ID  SUITE                            BITS PROT    CIPHER              MAC     KEYX
 0: 49195  ECDHE-ECDSA-AES128-GCM-SHA256    128  TLS1.2  AES-GCM             SHA256  ECDHE_ECDSA
 1: 49161  ECDHE-ECDSA-AES128-SHA           128  TLS1   AES                 SHA     ECDHE_ECDSA
 2: 49161  ECDHE-ECDSA-AES128-SHA           128  TLS1.1  AES                 SHA     ECDHE_ECDSA
 3: 49161  ECDHE-ECDSA-AES128-SHA           128  TLS1.2  AES                 SHA     ECDHE_ECDSA
 4: 49187  ECDHE-ECDSA-AES128-SHA256        128  TLS1.2  AES                 SHA256  ECDHE_ECDSA
 5: 49196  ECDHE-ECDSA-AES256-GCM-SHA384    256  TLS1.2  AES-GCM             SHA384  ECDHE_ECDSA
 6: 49162  ECDHE-ECDSA-AES256-SHA           256  TLS1   AES                 SHA     ECDHE_ECDSA
 7: 49162  ECDHE-ECDSA-AES256-SHA           256  TLS1.1  AES                 SHA     ECDHE_ECDSA
 8: 49162  ECDHE-ECDSA-AES256-SHA           256  TLS1.2  AES                 SHA     ECDHE_ECDSA
 9: 49188  ECDHE-ECDSA-AES256-SHA384        256  TLS1.2  AES                 SHA384  ECDHE_ECDSA
10: 52393  ECDHE-ECDSA-CHACHA20-POLY1305-SHA256   256  TLS1.2  CHACHA20-POLY1305   NULL    ECDHE_ECDSA
11: 49160  ECDHE-ECDSA-DES-CBC3-SHA         168  TLS1   DES                 SHA     ECDHE_ECDSA
12: 49160  ECDHE-ECDSA-DES-CBC3-SHA         168  TLS1.1  DES                 SHA     ECDHE_ECDSA
13: 49160  ECDHE-ECDSA-DES-CBC3-SHA         168  TLS1.2  DES                 SHA     ECDHE_ECDSA

To do so, just replace 'DEFAULT' by 'ECDHE_ECDSA' in Ciphers section and try again.

If you get an error during this connection it's because you facing some bug.

Some extra messages could be displayed in /var/log/ltm.

Anyway, have you checked that your cert allows you for using 'ecdhe-ecdsa'?

"When configuring an SSL profile, if an ecdhe-ecdsa cipher is selected in the 'ciphers' field, make sure ecdhe-ecdsa key/cert is also configured."

REF - https://cdn.f5.com/product/bugtracker/ID529400.html

Regards,

Dario.