Canadian-domain-ssl

As the need for internet security rises, it is important that server administrators keep up with security protocols and disable obsolete and insecure protocols. If you’re running a website on IIS, then you’ll want to read this article and check your servers. Basically, you’ll want to disable the older protocols and ciphers through your registry. Unfortunately, if any of your visitors are using out-dated web browsers, they might run into some issues, but that should be their concern since your concern is keeping your server secure and providing the best security you can for your visitors.

Microsoft has explained how to do this manually. The full list of cipher suites that are supported is also outlined by Microsoft. In addition, you can also follow these steps to manually enable these changes.

The best practices cipher suite order:
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P521
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P521
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P521
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P521
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P256
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA

The default cipher suite order:
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P521
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P521
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P384
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P521
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P521
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P256
TLS_RSA_WITH_AES_256_GCM_SHA384*
TLS_RSA_WITH_AES_128_GCM_SHA256*
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P521
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P384
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P521
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P384
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P521
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P384
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P521
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P384
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P521
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P521
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P256
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
TLS_DHE_DSS_WITH_AES_256_CBC_SHA
TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
TLS_DHE_DSS_WITH_AES_128_CBC_SHA
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
TLS_RSA_WITH_RC4_128_SHA

If you do not want to configure these manually, then I suggest you check out a nifty little tool called IIS Crypto.

IIS Crypto was created to simplify enabling and disabling various protocols and cipher suites on servers running IIS, and it sets a few registry keys to enable/disable protocols, ciphers and hashes, as well as reorder cipher suites. All the changes are made following Microsoft’s best practices.

One of the nice things about IIS Crypto, in my opinion, is that it also supports pre-defined templates that can be set with a single button click:

PCI – Disables everything except SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2, RC4 128, Triple DES 168, AES 128, AES 256, MD5, SHA1, DH, and PKCS.
FIPS 140-2 – Disables everything except TLS 1.0, TLS 1.1, TLS 1.2, Triple DES 168, AES 128, AES 256, SHA1, DH, and PKCS.
BEST PRACTICES – The same as PCI, but also reorders the cipher suite.

iis-crypto-1

Once used, IIS Crypto modifies some registry key and child nodes. Each registry key has an “Enabled” value that is set, while protocols have an additional value named “DisabledByDefault” that is also set.

To enable/disable protocols, ciphers and hashes:

HKLMSYSTEMCurrentControlSetControlSecurityProvidersSCHANNEL

To reorder the cipher suites:

HKLMSOFTWAREPoliciesMicrosoftCryptographyConfigurationSSL0010002

It was tested on Windows Server 2003, 2008, 2008 R2 and 2012 and 2012 R2.

Note for servers running Remote Desktop Services (RDS): The default security layer in RDP is set to “Negotiate”, which supports both SSL (TLS 1.0) and the RDP Security Layer. However, if you set the security layer to SSL (TLS 1.0) and disable TLS 1.0 in IIS Crypto you will be unable to connect to RDP.

To check your settings, open Remote Desktop Session Host Configuration in Administrative Tools and double click RDP-Tcp under the Connections group. If it is set to SSL (TLS 1.0), make sure that you do not disable TLS 1.0 in IIS Crypto.