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ciphers applied to client SSL profile for allow only tls 1.2 not working?

Hi ,

I applied below cipher settings for client SSl profile and applied to VIP 443. But when i try to access the website from any browser, settings in browser unchecked for tls 1.2 and allowed tls 1.0 , 1.1 is working across all clients.

any idea how to monitor the inbound traffic and any other settings need to be add, Guide me on this.

ciphers DEFAULT:!SSLv2:!EXPORT40:!EXP:!LOW:!SSLv3:!RC4-SHA:AES128-SHA:AES256-SHA:!DES-CBC3-SHA:!TLSv1:!TLSv1_1

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USER ACCEPTED ANSWER & F5 ACCEPTED ANSWER

Can you login to the LTM and run the below command & share to us, Is your applied CIPHER reflecting in there ?

tmsh list ltm profile client-ssl <your-custom-clientsslname> ciphers options

If you wanna make the change, the right way to stop the Tls1.0 & Tls1.1 protocol is to control it in the options parameter,

tmsh modify ltm profile client-ssl <your-custom-clientsslname> options { dont-insert-empty-fragments no-sslv2 no-sslv3 no-tlsv1 no-tlsv1.1 }

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Comment made 13-Jul-2018 by IRONMAN 197

I am getting below for when i list ciphers for SSL profile, I was told it is key exchange taking the TLS 1.0, but restricted to Tls.1.2 ? some answer from security team

ciphers DEFAULT:!SSLv2:!EXPORT40:!EXP:!LOW:!SSLv3:!RC4-SHA:AES128-SHA:AES256-SHA:!DES-CBC3-SHA:!TLSv1:!TLSv1_1

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Comment made 25-Jul-2018 by Jhaunu Gupta 261

tmsh modify ltm profile client-ssl <your-custom-clientsslname> options { dont-insert-empty-fragments no-sslv2 no-sslv3 no-tlsv1 no-tlsv1.1 }

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USER ACCEPTED ANSWER & F5 ACCEPTED ANSWER

IRONMAN,

I would look to perform a tcpdump/ssldump to see what's going on, see

Overview of packet tracing with the ssldump utility

Also, if you use Putty to connect to your BIG-IP and perform the following command tmm --clientciphers 'DEFAULT:!SSLv2:!EXPORT40:!EXP:!LOW:!SSLv3:!RC4-SHA:AES128-SHA:AES256-SHA:!DES-CBC3-SHA:!TLSv1:!TLSv1_1' it will outline which ciphers are being presented by the clientssl profile.

Hope this helps,

N

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Comment made 16-Aug-2018 by IRONMAN 197

I am getting below for commands output and still users are able to access with tls 1.0 from browser.

# tmm --clientciphers 'DEFAULT:!SSLv2:!EXPORT40:!EXP:!LOW:!SSLv3:!RC4-SHA:AES128-SHA:AES256-SHA:!DES-CBC3-SHA:!TLSv1:!TLSv1_1'
       ID  SUITE                            BITS PROT    METHOD  CIPHER  MAC     KEYX
 0:    61  AES256-SHA256                    256  TLS1.2  Native  AES     SHA256  RSA
 1:    53  AES256-SHA                       256  TLS1.2  Native  AES     SHA     RSA
 2:    53  AES256-SHA                       256  DTLS1   Native  AES     SHA     RSA
 3:    60  AES128-SHA256                    128  TLS1.2  Native  AES     SHA256  RSA
 4:    47  AES128-SHA                       128  TLS1.2  Native  AES     SHA     RSA
 5:    47  AES128-SHA                       128  DTLS1   Native  AES     SHA     RSA
 6: 49192  ECDHE-RSA-AES256-SHA384          256  TLS1.2  Native  AES     SHA384  ECDHE_RSA
 7: 49172  ECDHE-RSA-AES256-CBC-SHA         256  TLS1.2  Native  AES     SHA     ECDHE_RSA
 8: 49191  ECDHE-RSA-AES128-SHA256          128  TLS1.2  Native  AES     SHA256  ECDHE_RSA
 9: 49171  ECDHE-RSA-AES128-CBC-SHA         128  TLS1.2  Native  AES     SHA     ECDHE_RSA
10: 49170  ECDHE-RSA-DES-CBC3-SHA           192  TLS1.2  Native  DES     SHA     ECDHE_RSA

I don't see TLS 1.0, but still users are able to access the VIP with browser only enabled tls 1.0

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USER ACCEPTED ANSWER & F5 ACCEPTED ANSWER

Got solution from one of the team, but not sure what it does, please any one explain

clientssl cert default.crt key default.key chain none ciphers DEFAULT:!SSLv2:!EXPORT40:!EXP:!LOW:!SSLv3:!RC4-SHA:AES128-SHA:AES256-SHA:!DES-CBC3-SHA:!TLSv1:!TLSv1_1:!RSA

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Comments on this Answer
Comment made 25-Jul-2018 by boneyard 5579

it is your team i assume, shouldn't you ask them then? do you have any colleagues with F5 knowledge that can help out?

you can't really solve this with putting some strings of ciphers here and expect someone to understand the issue and solve it. you gotta look at what happens, understand it and go from there.

there are several tools you can use to check your website when you apply a certain cipher string. you can use the advice from nathan to determine which ciphers (if any) the big-ip uses based on that cipher string and your TMOS version. you haven't even shared that part of the puzzle.

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Comment made 25-Jul-2018 by IRONMAN 197

Please give tools , i will check it out and update here with details?

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Comment made 26-Jul-2018 by boneyard 5579

nicely ignoring my question on asking your team and colleagues.

as nathan states: login to BIG-IP, run tmm --clientciphers '[cipher string]'

as for external:

https://www.ssllabs.com/ssltest/

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Comment made 26-Jul-2018 by IRONMAN 197

Thanks, Surely i ask them to provide reason behind it and also i dig it.

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