Robert Lockard

Sep 15, 2016

This post comes to us from a guest blogger, Robert Lockard. Robert is an Oracle ACE with over 30 years experience as an Oracle DBA / Designer and Developer. He has spent the past 10 years focusing on database security. Robert frequently speaks at conferences all over the world, teaching DBA’s and Developers how to secure their data. You can follow him on twitter at @YourNavionPilot and read more of his blogs at http://www.oraclewizard.com.

I have four mantras for any system I’m involved in: Stability, Security, Accuracy and Performance.

When it comes to information security in the cloud, there are lots of recommendations for vendors and customers to consider. When I am called into customer sites to ensure their data is properly protected, my first step is making sure the person connecting to the database is authenticated properly and that encryption has been properly set up, along with a host of other related things. The amount of work required just to get data encrypted, make sure there is no ghost data, and ensure there is no spillage is a difficult process. From my perspective, Snowflake makes the end-to-end encryption easy because encryption is turned on by default. Your data is being encrypted from day one.

Here is my best advice on how to insure your critical business data is secure in the cloud along with my review of how Snowflake addresses these issues.

#1 – Demand Multi-factor Authentication

Snowflake supports using DUO multi-factor authentication to ensure the user who is authenticated to the database is also authorized. Stolen credentials are one of the top ways bad actors get in where they do not belong. The username / password paradigm of authentication has been around for several decades. Username / password harvesting and many of the data breaches, could be reduced by following best practices and a best practice is to use multi-factor authentication. This is something you know and something you have. When you authenticate with a username / password, a token will display a code;  you enter that code into the system and then you are authenticated. This is something Snowflake has built into their system. Multi-factor authentication is not an add-on option; it comes standard with their product.

In addition, Snowflake’s implementation of DUO also allows a verification request to be sent to a mobile device. When you enter your username / password, a request is sent to your mobile device. If you approve the request, you are connected. The beauty of this is, most of us always have our mobile phones with us. If you get a request that you did not originate, you know someone else is trying to use your credentials to get into the system. When you reject the request, they will be locked out.

#2 – Demand End-to-end Encryption

The customer should require end-to-end encryption from any cloud provider they decide to use. Snowflake delivers AES-256 encryption at no extra cost. The AES standard was adopted in 2001 by the National Institute of Standards and Technology (NIST). The AES standard has displaced the older DES standard. The AES standard uses 128 block sizes with three keys sizes 128, 192 and 256 bits. AES encryption is the US Government standard for strong encryption and has been adopted by financial, government and other commercial entities world wide.

#2a – Demand Sophisticated Encryption Key Management

Snowflake uses the Amazon Hardware Security Module (HSM) to manage sophisticated key structures such as key wrapping, key rotation and re-keying.

Key Wrapping (aka Hierarchical Keys)

Key wrapping has become the industry standard. Oracle provides it in Transparent Data Encryption with a master key that is stored outside the database to decrypt the keys that are used to secure the data. Microsoft SQL Server uses a certificate that is stored outside the database to decrypt the key that is used to decrypt the data. Snowflake uses four levels of keys to encrypt customers data.

Using this model, each customer’s data is encrypted with a unique set of keys. This way, customer “A”s data is encrypted with a different set of keys then customer “B”. By using multiple customer keys, each customer’s data is segregated, and secured, from the others.

See the Snowflake Encryption Key Management blog post for more details.

Cryptologic Key Life Time

National Institute of Standards (NIST) recommends having a policy in place so each key has a limited lifetime. The longer a key is in use, the greater the odds it will be compromised (see NIST Encryption Key Management Recommendation for more details). Snowflake uses two methods to control the lifetime of keys: key rotation and rekeying.

1) Cryptologic Key Rotation

One way to minimize the impact of a cryptologic key being compromised is to rotate the keys at a set interval. Snowflake rotates keys at a system defined interval. This ensures if a cryptologic key is compromised then the amount of data at risk is minimized.

The easy way to understand key rotation is this. Data is encrypted and decrypted using a key and, after a set period of time, another key is added; all new data is encrypted and decrypted with this new key and old data is decrypted with the old key. Again, see the Snowflake Encryption Key Management blog post for more details.

The advantage of using key rotation is two fold: a) Because you are adding a key, you don’t have to change the keying on the data that had been encrypted; you get performance. b) Because now there are multiple keys; if any key is compromised only a subset of information is vulnerable.

2) Cryptologic Rekeying

As an additional security option, customers can choose to have their data rekeyed annually. By rekeying the data annually, Snowflake minimizes the amount of time a key is in use, thereby minimizing the odds a cryptologic key will be compromised. Once data is rekeyed, the old keys are destroyed.

Network Encryption

Now we need to deal with data that is moving over the network. All network communications between loading the data and analyzing the data is encrypted using TLS (see Advantages of Using TLS for more details). In addition, for ESD (Enterprise with Sensitive Data) customers, all internal network communications is encrypted using TLS.

By using the TLS standard, Snowflake has implemented the industry best practice.

What about Performance and Stability?

There exists a perception that encryption has a negative performance impact on CPU. The HSM performs a variety of functions. It manages encrypting and decrypting keys, handles key rotation and rekeying. In addition, the HSM is only used to wrap and unwrap account master keys. All remaining encryption is performed by other services in the background, resulting in no impact on customer workloads.

The hardware encryption module is also tamper-resistant. Efforts to tamper with the hardware encryption module will shut the HSM down, yet Snowflake has configured the HSM to be stable and reliable.

Conclusion

Based on my evaluation, by using Snowflake, the customer gets three of my four mantras:

Security: You get multi-factor authentication and end-to-end encryption right out of the box.

Stability: Snowflake has configured the HSM to be very stable, plus it lives on AWS which has proven to be a very stable cloud platform.

Performance: Snowflake’s use of the Amazon Elastic Compute Cloud gives performance on demand.

My fourth manta, Accuracy, is up to you.