Re: [TLS] [CAUTION] Re: Fwd: New Version Notification for draft-moriarty-tls-oldversions-diediedie-00.txt

mrex@sap.com (Martin Rex) Tue, 10 July 2018 20:31 UTC

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To: mrex@sap.com
Date: Tue, 10 Jul 2018 22:31:32 +0200 (CEST)
CC: Andrei Popov <Andrei.Popov=40microsoft.com@dmarc.ietf.org>, "<tls@ietf.org>" <tls@ietf.org>
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From: mrex@sap.com (Martin Rex)
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Subject: Re: [TLS] [CAUTION] Re: Fwd: New Version Notification for draft-moriarty-tls-oldversions-diediedie-00.txt
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mrex@sap.com (Martin Rex) wrote:
> Andrei Popov <Andrei.Popov=40microsoft.com@dmarc.ietf.org>; wrote:
>>
>> On the recent Windows versions, TLS 1.0 is negotiated more than 10%
>> of the time on the client side (this includes non-browser connections
>> from all sorts of apps, some hard-coding TLS versions),
>> and TLS 1.1 accounts for ~0.3% of client connections.
> 
> "On recent Windows versions" sounds like figure might not account
> for Windows 7 and Windows Server 2008R2, about half of the installed
> base of Windows, and where the numbers are likely *MUCH* higher.
> 
> When troubleshooting TLS handshake failures, I sometimes trying
> alternative SSL/TLS clients on customer machines through remote support,
> and it seems when I run this command on a Windows 2012R2 server:
> 
>         powershell "$web=New-Object System.Net.WebClient ; $web.DownloadString('https://www.example.com/')" 2>&1
> 
> it connects with TLSv1.0 only, and this is a client-side limitation.
> 
> To make it use TLSv1.2, I would have to use
> 
>         powershell "[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 ; $web=New-Object System.Net.WebClient ; $web.DownloadString('https://www.example.com/')" 2>&1
> 
> i.e. explicit opt-in.


btw. I checked this on a Windows 10 (1709) machine, and it's powershell also
tries connecting with TLSv1.0 only.

To me, it looks more like 100% of the Microsoft Windows installed
base not being ready for a TLSv1.2-only world.


-Martin