[Ach] POODLE

Alain Wolf alain at alainwolf.ch
Wed Oct 15 09:44:21 CEST 2014


Am 15.10.2014 um 09:32 schrieb Alain Wolf:
> Am 15.10.2014 um 09:18 schrieb Alexander Wuerstlein:
>> On 2014-10-15T08:39, L. Aaron Kaplan <aaron at lo-res.org> wrote:
>>> ---
>>> Mobile
>>>
>>>
>>>> On 15.10.2014, at 01:50, Aaron Zauner <azet at azet.org> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Guess it's good we opted to forbid SSLv3 where possible:
>>>>
>>>> https://www.imperialviolet.org/2014/10/14/poodle.html
>>>>
>>> ACK! 
>>> We should also reference their paper and explain why we disabled it. 
>>>
>>> BTW: for that we'll need the cipherstringB macro again - to replace the cipherstring in the document in a consistent way. 
>> Yes, but I would leave out the 'where possible'. Using Cleartext and a
>> warning page or no connection at least somehow signals danger to the end
>> user, whereas current user agents don't (yet) warn on SSL3-connections.
>> So I would recommend turning off SSL3 on a server, period. 
>>
>> Is there any data as for how frequent SSL3-only user-agents still are?
> Maybe Cloudflare. I remember them having interesting stats on RC4, they
> should have that on SSLv3 too.
> https://blog.cloudflare.com/the-web-is-world-wide-or-who-still-needs-rc4/
I was too slow, the numbers are already there:

https://blog.cloudflare.com/sslv3-support-disabled-by-default-due-to-vulnerability/
>
>
>       SSLv3 Usage Stats
>
> Across our network, 0.09% of all traffic is SSLv3. For HTTPS traffic,
> 0.65% across our network uses SSLv3. The good news is most of that
> traffic is actually attack traffic and some minor crawlers. For real
> visitor traffic, today 3.12% of CloudFlare's total SSL traffic comes
> from Windows XP users. Of that, 1.12% Windows XP users connected using
> SSLv3. In other words, even on an out-of-date operating system, 98.88%
> Windows XP users connected using TLSv1.0+ — which is not vulnerable to
> this vulnerability.
>
> Beyond human browser traffic, some crawlers default to SSLv3. The
> largest crawler we see defaulting to SSLv3 is Pingdom's. Pingdom is a
> CloudFlare partner. We alerted them to this issue and are actively
> working with them to ensure that their crawler will support HTTPS over
> a protocol other than SSLv3.
>


>
>> Even ancient Internet Explorers on WinXP can be configured[0] to support
>> TLS 1.0 after all, so I would not include a 'where possible' for those
>> weird setups: such an addition would maybe confuse more server admins
>> into "erring on the side of (misguided) caution", leaving them with SSL3
>> enabled "because I might have compatibility problems".
>>
>>
>>
>> Ciao,
>>
>> Alexander Wuerstlein.
>>
>>
>> [0] says wikipedia: http://en.wikipedia.org/wiki/Transport_Layer_Security
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>
>
>
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