Google Chrome obsolete cryptography



  • I have a apache server running and following configuration for ssl:

     Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
     SSLProtocol -all +TLSv1.2
     SSLCompression Off
     SSLHonorCipherOrder on
     SSLCipherSuite "ECDH+AESGCM256:DH+AESGCM256:ECDH+AES256:SH+AES256:RSA+AESGCM256:RSA+AES256:!aNULL:!MD5:!kEDH:!DSS"
    

    In Chrome i got the same "problem" as the user asked here: Google Chrome "Your connection to website is encrypted with obsolete cryptography"

    Can anyone tell me what i have to change in this configuration that i get "modern cryptography"?

    My certificate is signed with SHA512withRSA and I only want to support 256-Bit chiphers.



  • When looking what ciphers you actually provide:

    openssl ciphers -V 'ECDH+AESGCM256:DH+AESGCM256:ECDH+AES256:SH+AES256:RSA+AESGCM256:RSA+AES256:!aNULL:!MD5:!kEDH:!DSS'
    
          0xC0,0x30 - ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AESGCM(256) Mac=AEAD
          0xC0,0x2C - ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AESGCM(256) Mac=AEAD
          0xC0,0x28 - ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA384
          0xC0,0x24 - ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA384
          0xC0,0x14 - ECDHE-RSA-AES256-SHA    SSLv3 Kx=ECDH     Au=RSA  Enc=AES(256)  Mac=SHA1
          0xC0,0x0A - ECDHE-ECDSA-AES256-SHA  SSLv3 Kx=ECDH     Au=ECDSA Enc=AES(256)  Mac=SHA1
          0xC0,0x32 - ECDH-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AESGCM(256) Mac=AEAD
          0xC0,0x2E - ECDH-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AESGCM(256) Mac=AEAD
          0xC0,0x2A - ECDH-RSA-AES256-SHA384  TLSv1.2 Kx=ECDH/RSA Au=ECDH Enc=AES(256)  Mac=SHA384
          0xC0,0x26 - ECDH-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH/ECDSA Au=ECDH Enc=AES(256)  Mac=SHA384
          0xC0,0x0F - ECDH-RSA-AES256-SHA     SSLv3 Kx=ECDH/RSA Au=ECDH Enc=AES(256)  Mac=SHA1
          0xC0,0x05 - ECDH-ECDSA-AES256-SHA   SSLv3 Kx=ECDH/ECDSA Au=ECDH Enc=AES(256)  Mac=SHA1
          0x00,0x9D - AES256-GCM-SHA384       TLSv1.2 Kx=RSA      Au=RSA  Enc=AESGCM(256) Mac=AEAD
          0x00,0x3D - AES256-SHA256           TLSv1.2 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA256
          0x00,0x35 - AES256-SHA              SSLv3 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA1
    

    You provide ciphers with GCM, which is what you need for "modern cryptography". But you provide only ciphers with SHA384, which is not supported by Chrome. Thus none of the GCM ciphers can be used by the client and only the "obsolete cryptography" ciphers can be used.

    My certificate is signed with SHA512withRSA and I only want to support 256-Bit chiphers.

    You should provide adequate security and not "mine is bigger than yours" security. AES128-GCM-SHA256 is adequate and supported by Chrome.

    I recommend reading https://wiki.mozilla.org/Security/Server_Side_TLS#Modern_compatibility




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