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SSL Vulnerabilities and West Wind Products


Wednesday, October 15, 2014, 6:32:36 PM

Several people have sent me frantic email messages today in light of the latest POODLE SSL vulnerability and whether it affects West Wind products.

The vulnerability essentially deals with older SSL protocol bugs and the concern is especially on the server that protocol fallback from TLS to SSL can cause problems. Current protocols are TLS vs. the older SSL technology. Only the older SSL stacks are vulnerable. This is most critical on Web Servers, and you'll want to disable the older SSL protocols on IIS and leave only TLS enabled. TLS is the newer standard that superseded  SSL, although we still talk about SSL certificates – most modern certificates are actually TLS certificates and have support for SSL for fallback validation.

You can check your server’s SSL certificate status here:
https://www.ssllabs.com/ssltest/index.html

You’ll want to see that all versions of SSL are either disabled or at the very least that the server doesn’t support protocol fallback to SSL protocols.

When I ran this for my site running Server 2008 (IIS 7.0) I found SSL3 enabled, but the server not supporting automatic protocol fallback which avoids the main POODLE issue. I’ve since disabled SSL V3 on the server. The good news is, that while the certificate isn’t using maximum strength, the server was not found to be vulnerable from this issue even with the default settings in place.

Disabling SSL on IIS

If you see that SSL versions are enabled even if you have TLS certificates (which just about all of them should be by now) you can disable specific protocols. This is done through registry keys, but be aware that this is global for the entire machine. You can disable/enable protocols for both the client and server.

Here's a KB article from Microsoft to check out that tells you how to disable older SSL protocols.
http://support.microsoft.com/kb/187498

SSL and WinInet

The West Wind Client Tools and specifically the wwHTTP class rely on the Windows WinInet library to provide HTTP services. The POODLE issue is much less critical for the client as the client is the actually attacking entity. But I double checked here on my local machine and I can see that WinInet uses TLS 1.2 on my Windows 8.1 when connecting to a certificate on the server.

Capturing an https:// session from Fiddler shows the following request header signature on the CONNECT call:

Version: 3.3 (TLS/1.2)
Random: 54 3F 15 D6 B5 3E 6B F5 AD 71 41 FB 4C 39 B9 30 C5 21 04 A4 76 7F 87 A5 1A BA D6 83 19 B3 10 3B
SessionID: empty

which suggests TLS/1.2 as the initial request sent.

I don’t know what older versions of Windows – XP in particular use – but I suspect even XP will be using TLS/1.0 at the very least at this point. Maybe somebody can check (Use Fiddler, disable Decrypt HTTPS connections option, then capture HTTPS requests and look at the raw request/response headers.

Nothing to see here

From the West Wind perspective this issue is not specific to the tools, but to the operating system. So make sure the latest patches are installed and that if you have to remove the server SSL certificates. Client software is not really at risk, since the attack vector is a receiving Web Server. Regardless even the client tools appear to be using the latest safer protocols and so any West Wind tools are good to go.

Posted in: Web Connection    Web Development    Windows

 



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