[Freeipa-devel] FreeIPA and modern requirements on certificates

[Alexander Bokovoy]

On Fri, 08 Jan 2016, Martin Kosek wrote:
>On 01/08/2016 02:17 PM, Fraser Tweedale wrote:
>> On Fri, Jan 08, 2016 at 02:02:07PM +0100, Martin Kosek wrote:
>>> On 01/08/2016 01:56 PM, Fraser Tweedale wrote:
>>>> On Fri, Jan 08, 2016 at 01:26:57PM +0100, Martin Kosek wrote:
>>>>> Hi Fraser and other X.509 SMEs,
>>>>>
>>>>> I wanted to check with you on what we have or plan to have with respect to
>>>>> certificate/cipher strength in FreeIPA.
>>>>>
>>>>> When I visit the FreeIPA public demo for example, I usually see following
>>>>> errors with recent browsers:
>>>>>
>>>>> * Your connection to ipa.demo1.freeipa.org is encrypted using obsolete cypher
>>>>> suite.
>>>>>  - The connection uses TLS 1.2
>>>>>  - The connection is encrypted ising AES_128_CBC, with HMAC-SHA1 for message
>>>>> authentication and RSA as the key exchange mechanism
>>>>>
>>>> This is a cipher suite / ordering issue, not related to certificate.
>>>>
>>>>> I usually do not see the common
>>>>> * Certificate chain contains a certificate signed with SHA-1
>>>>> error, but I am not sure if we are covered for this one.
>>>>>
>>>> We are using sha256 for IPA CA and default profiles.  Customers
>>>> could still modify the profile or add profiles to sign using an
>>>> obsolete hash, if they wanted to, but our default is good.
>>>>
>>>>>
>>>>> When I tested the FreeIPA demo with
>>>>> https://www.ssllabs.com/ssltest/analyze.html?d=ipa.demo1.freeipa.org
>>>>> (and ignore the trust issues), we get the mark B with following warnings:
>>>>>
>>>>> * This server accepts RC4 cipher, but only with older protocol versions. Grade
>>>>> capped to B.
>>>>>
>>>>> * The server does not support Forward Secrecy with the reference browsers.
>>>>>
>>>> Again a cipher suite tweak will address this.
>>>>
>>>>>
>>>>> What do we miss to turn out Grade A, which is obviously something expected from
>>>>> security solution like FreeIPA? Is it just about ECC support
>>>>> (https://fedorahosted.org/freeipa/ticket/3951) or also maybe some change to our
>>>>> default certificate profiles?
>>>>>
>>>> Based on what you've written, it is just the cipher suite that needs
>>>> changing, and maybe a setting about favouring server cipher order
>>>> over client order.  ECC certificate support is not needed (yet) and
>>>> the default profile is fine, w.r.t. hash used for signing.
>>>>
>>>> One important modern certificate requirement is to always include a
>>>> SAN dnsName for the subject, as required by RFC 2818; this is ticket
>>>> #4970 and it is on my radar.
>>>>
>>>> Cheers,
>>>> Fraser
>>>
>>> Should I then file a ticket to fix the cipher suite? (I did not fully
>>> understand the specifics though).
>>>
>> Yes.  I have not checked yet, but we are possibly using
>> stock-standard mod_nss configuration (as shipped by the RPM).  If
>> so, we should file a ticket against mod_nss to improve their
>> defaults.
>
>Right. In nss.conf, I see this default cipher suite:
>
>NSSCipherSuite
>+rsa_rc4_128_md5,+rsa_rc4_128_sha,+rsa_3des_sha,-rsa_des_sha,-rsa_rc4_40_md5,-
>
>rsa_rc2_40_md5,-rsa_null_md5,-rsa_null_sha,+fips_3des_sha,-fips_des_sha,-fortezza,-fortezza_rc4_128_sha,-fortezza_null,-rsa_des_56_sha,-rsa_rc4_56_sha,+rsa_aes_128_sha,+rsa_aes_256_sha
>
>It certainly makes me little nervous. In 389-ds-base case, we had a similar
>list and solved it my using the list directly from NSS:
>
>https://fedorahosted.org/389/ticket/47838
>https://fedorahosted.org/freeipa/ticket/4395
>
>CCing Rob here.
Here is what I have in my setup that goes to A- according to ssllabs:
NSSCipherSuite -rsa_rc4_128_md5,-rsa_rc4_128_sha,+rsa_3des_sha,-rsa_des_sha,-rsa_rc4_40_md5,-rsa_rc2_40_md5,-rsa_null_md5,-rsa_null_sha,+fips_3des_sha,-fips_des_sha,-fortezza,-fortezza_rc4_128_sha,-fortezza_null,-rsa_des_56_sha,-rsa_rc4_56_sha,+rsa_aes_128_sha,+rsa_aes_256_sha

NSSProtocol TLSv1.0,TLSv1.1,TLSv1.2

This gets A- due to lack of forward secrecy support.

-- 
/ Alexander Bokovoy