Ssl – Enabling cipher TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa) on Windows Server 2003+ISA 2006

isa-serverSecuritysslwindows-server-2003

I have been given a task to disable all "weak" ciphers/protocols on our very old ISA server based on Windows Server 2003. I have disabled all protocols but TLS1.0, and all ciphers but RC2/128, RC4/128 and Triple DES 168/168. But Qualys SSL Labs test utility does not display me that I have a 3DES encryption available on my ISA server. The only cipher suites listed are:

TLS_RSA_WITH_RC4_128_MD5 (0x4)  
TLS_RSA_WITH_RC4_128_SHA (0x5)

This KB says that when Triple DES 168 cipher is enabled, the TLS_RSA_WITH_3DES_EDE_CBC_SHA cipher suite is available. However, it is not. We need this cipher suite to allow a Windows 8.1 Phone connecting to ActiveSync published by this ISA. What could be the reason of 3DES encryption to be unavailable in this configuration, and what should we do in order to allow the connection for a Windows 8.1 phone without being vulnerable to POODLE?

EDIT: There was apparently a server-side malfunction of some sort, a reboot fixed 3DES availability, although the same KB states that registry change should have worked at once. I've got another server with the same problem, got it fixed with registry modification only, though.

Best Answer

If your registry change didn't take effect immediately, then just restart your computer.

Related Solutions

ISA 2006 can run on Windows Server 2008

No.

ISA uses a kernal mode driver to perform its firewall duties which is not compatible with Server 2008 (which has a very different network stack).

Forefront Threat Management Gateway (TMG) 2010 has been released, and is the new version of ISA. It is supported on 2008 x64.

Ssl – RC4 cipher not working on Windows 2008 R2 / IIS 7.5

The issue why RC4 isn't working is that is has to be set to 0xfffffff or 4294967295 in the registry, not 1 to enable it.

Here's some PowerShell functions which were used to set our IIS installs up with the PCI compliant:

This function is used to enable/disable required protocols

function Set-IISSecurityProtocols {
$protopath = "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols"
& reg.exe add "$protopath\PCT 1.0\Server" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$protopath\SSL 2.0\Server" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$protopath\SSL 3.0\Server" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.0\Server" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.1\Server" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.1\Server" /v DisabledByDefault /t REG_DWORD /d 00000000 /f
& reg.exe add "$protopath\TLS 1.2\Server" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.2\Server" /v DisabledByDefault /t REG_DWORD /d 00000000 /f
& reg.exe add "$protopath\TLS 1.1\Client" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.1\Client" /v DisabledByDefault /t REG_DWORD /d 00000000 /f
& reg.exe add "$protopath\TLS 1.2\Client" /v Enabled /t REG_DWORD /d 00000001 /f
& reg.exe add "$protopath\TLS 1.2\Client" /v DisabledByDefault /t REG_DWORD /d 00000000 /f

}

And this function is where you set what ciphers are allowed to be used, or not used

function Set-IISSupportedCiphers {
$cipherpath = "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers"
& reg.exe add "$cipherpath\NULL" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\DES 56/56" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC2 40/128" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC2 56/128" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC2 128/128" /v Enabled /t REG_DWORD /d 00000000 /f 
& reg.exe add "$cipherpath\RC4 40/128" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC4 56/128" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC4 64/128" /v Enabled /t REG_DWORD /d 00000000 /f
& reg.exe add "$cipherpath\RC4 128/128" /v Enabled /t REG_DWORD /d 4294967295 /f
& reg.exe add "$cipherpath\Triple DES 168/168" /v Enabled /t REG_DWORD /d 4294967295 /f
& reg.exe add "$cipherpath\AES 128/128" /v Enabled /t REG_DWORD /d 4294967295 /f 
& reg.exe add "$cipherpath\AES 256/256" /v Enabled /t REG_DWORD /d 4294967295 /f

}

Once these changes have been set (A reboot is required afaik) you then can set the priority in which the ciphers are used.

To immune the BEAST vulnerability it's reccomended you used RC4 first as outlined @ http://www.phonefactor.com/blog/slaying-beast-mitigating-the-latest-ssltls-vulnerability.php

This will be the case until either

All browsers patch the BEAST vulnerability
Or everyone starts supporting TLS1.2

Best Answer

Related Solutions

ISA 2006 can run on Windows Server 2008

Ssl – RC4 cipher not working on Windows 2008 R2 / IIS 7.5

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