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JD1's avatar
JD1
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Dec 13, 2017

TMUI / Configuration WebUI - TLS/SSL Configuration - ECDHE

Hi All, I'm currently using BIG-IP 11.6.2 HF1. I'm required to secure the Management WebUI ciphers offered out. I'd prefer to drop all key exchange methods except for ECDHE. However, it seems...
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  • nitass's avatar
    nitass
    Dec 21, 2017

    But the point being is that the command sys httpd ssl-ciphersuite on 11.6.x, doesn't seem to then correctly configure Apache services to use this for the TMUI.

     

    i understand this has been corrected in 12.0.

     

Ashwin_Venkat_1's avatar
Ashwin_Venkat_1
Historic F5 Account
Dec 14, 2017

Hi JD,

 

It is possible to disable all cipher suites other than the ones using ECDHE by appending ':!kDH:!kEDH:!kRSA' (without the quotes) to your cipher string within httpd. That should disable all DH, EDH/DHE, RSA key exchange based cipher suites. We need to specify the 'k' when enabling/disabling a certain key exchange when you modify the string on httpd, as it's based on the openssl stack. When enabling/disabling them within the SSL profiles, you don't need to specify that, because that is natively built into TMM and you can simply specify ':!DHE:!DH:!RSA' (without the quotes) to disable those key exchange based cipher suites.

 

Please let me know if this answers your question.

 

  • JD1's avatar
    JD1
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    Dec 14, 2017

    Hi Ashwin,

     

    Thanks for the reply.

     

    ECDHE needs to be there to begin with though, and isn't. It looks like 12.x does have it when I took it to lab. But I currently need it in 11.6.2.

     

    As for SSL profiles, I'm not looking at/referring to SSL profiles as this is outside of TMM and is Apache via mod_ssl (configured via the sys httpd ssl-ciphersuites).

     

    If there's anyway to enable ECDHE for Apache/Mod_SSL on 11.6.2, I'm all ears.

     

    Thanks,

     

    JD

     

  • Ashwin_Venkat_1's avatar
    Ashwin_Venkat_1
    Historic F5 Account
    Dec 21, 2017

    Hello JD,

    We do see that ECDHE based cipher suites being available on httpd for 11.6.x when I run the following command:

    openssl ciphers -v 'DEFAULT:!aNULL:!eNULL:!LOW:!RC4:!MD5:!EXP'

    If you see ECDHE not working in 11.6.x, then that is likely due to the older version of mod_ssl being used there. We have since upgraded the mod_ssl package in 12.x, which is why you see it there. In any case, the answer to your question is no. We don't support updating components/packages like mod_ssl.

  • JD1's avatar
    JD1
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    Dec 21, 2017

    Hi Ashwin,

    Absolutely, I also see openssl ciphers show the availability of ECDHE in the compiled openssl version (mentioned in original question).

    But the point being is that the command 

    sys httpd ssl-ciphersuite
    on 11.6.x, doesn't seem to then correctly configure Apache services to use this for the TMUI.

    I think you're confirming my suspicions, with mod_ssl possibly being outdated.

    (If you want to update your original answer, I'll mark as solved by it and accept we have to upgrade).

    Thanks,

    JD