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Nuruddin_Ahmed_'s avatar
Nuruddin_Ahmed_
Icon for Cirrostratus rankCirrostratus
Jun 20, 2016

Weak Ciphers

Hi,   We have applied verisign wildcard certificate for all our application as a client side certificate. We get B SSL ratings for our applications because of ciphers negotiated -   This server...
application delivery
big-ip
Hannes_Rapp's avatar
Hannes_Rapp
Icon for Nimbostratus rankNimbostratus
Jun 20, 2016

Assuming you want to keep everything as-is, and just take out DH:

(apply the custom cipher to your client-ssl profile)

DEFAULT:!DH

You can also see the full list of cipher suites that will still be enabled after your change.

(execute in BigIP BASH shell)

tmm --clientciphers 'DEFAULT:!DH'

More ways to configure your custom client-ssl cipher string, refer to https://support.f5.com/kb/en-us/solutions/public/13000/100/sol13171.html

  • Nuruddin_Ahmed_'s avatar
    Nuruddin_Ahmed_
    Icon for Cirrostratus rankCirrostratus
    Jun 20, 2016
    Hi Thanks for the quick reply. I applied below !DH:ECDHE:DHE:DHE_DSS:!LOW:!MEDIUM:@STRENGTH i am still failing in below - TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (0x9f) DH 1024 bits FS WEAK TLS_DHE_RSA_WITH_AES_256_CBC_SHA (0x39) DH 1024 bits FS WEAK TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA (0x16) DH 1024 bits FS WEAK
  • Hannes_Rapp's avatar
    Hannes_Rapp
    Icon for Nimbostratus rankNimbostratus
    Jun 20, 2016
    You can check here for optimal cipher configs: https://devcentral.f5.com/questions/pci-cipher-set . Perhaps PCI DSS 3.1 suite (my second reply in thread) will be good for you if you're looking to harden it a bit further. In regards to your recently reported 'weak' cipher suites, they are more in the pseudo-security category. You can safely ignore them without taking any action for now, but make sure to revise it somewhere in 2017.