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Our PCI compliance vendor requires that we disable all but RC4 encryption on our web server. Currently our apache config file looks like this:

SSLHonorCipherOrder On
SSLCipherSuite RC4-SHA:HIGH:!ADH:!AES256-SHA:!ECDHE-RSA-AES256-SHA384:!AES128-SHA:!DES-CBC:!aNull:!eNull:!LOW:!SSLv2

However, https://www.ssllabs.com reports the following ciphers are allowed:

  • TLS_RSA_WITH_RC4_128_SHA
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
  • TLS_RSA_WITH_3DES_EDE_CBC_SHA

How can I configure apache to only allow RC4?

Michael Hampton
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Daniel
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    Disable all but RC4? That's a new one. [Mitigating BEAST only requires that RC4-SHA be the first cipher offered](http://blog.phonefactor.com/2011/09/23/slaying-beast-mitigating-the-latest-ssltls-vulnerability/), which you had already done, not disabling everything else. – Michael Hampton Sep 20 '12 at 21:25
  • I didn't really want to do it, but when I called them, they insisted on only having RC4 enabled. (I think they would allow TLS 1.1 or 1.2 ciphers, but few clients support those) – Daniel Sep 20 '12 at 21:35
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    Oh, in that case they're idiots and you should go find another vendor. – Michael Hampton Sep 20 '12 at 21:35
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    What @MichaelHampton said. Your auditor's understanding of security (at least WRT crypto algorithms) is fundamentally flawed (and it's worth noting that RC4 (at least RC4-CBC) has its own theoretical flaws. You should find an auditor who understands this stuff a bit better, or bone up on it enough to argue them into submission... – voretaq7 Sep 20 '12 at 21:45

3 Answers3

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Interesting how things change. This is an old message but shows up in google searches so I should add that RC4 is now (2015) considered insecure and should not be used at all for PCI compliant sites.

Tim
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Turns out it was pretty easy. The "High" option in my original question was including the other ciphers. By reducing it to the following, I got what I wanted:

SSLCipherSuite RC4-SHA
Daniel
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403 labs is my PCI DSS compliance scan vendor. They require only RC4-SHA for SSL 3.0 and TLS 1.0. Their reasoning is that moving RC4-SHA to the top is the server preferred cipher suite not the clients. So the client could negotiate a block cipher on the list that is vulnerable to beast. Which all TLS 1.0 CBC ciphers are.

On my Apache server I only have RC4-SHA enabled. On my IIS boxes I have RC4-SHA plus all the TLS 1.2 only ciphers enabled.

msutton
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