Let's presume that it's time for your enterprise to choose and implement an SD-WAN solution. You've done the research, and have decided that SD-WAN makes sense, perhaps to supplement existing wide-area networks, perhaps to replace them. Maybe you'll use SD-WAN for expansion. Before you more forward, into the vendor-selection phase, here are four security questions you should think about.
But first, let me cross one specific question off your list: Encryption. Because they are fighting the (accurate) perception that traffic going over the public Internet is inherently vulnerable, SD-WAN vendors stress their strong encryption: gazillion-bit, end-to-end, military-grade, hardware-based, quantum-proof, blah blah blah. That's table stakes, my friends: Every name-brand SD-WAN encrypts traffic, and encrypts it really well. Data transiting over an Internet-based SD-WAN is encrypted in basically the same way as the traffic going over an Internet-based virtual private network (VPN) tunnel. So, don't worry about that.
1. How secure is the remote endpoint client?
With every SD-WAN, there must be some type of client on each end of the connection. In some cases, it's a hardware appliance. Often, it's pure software -- that's what you’ll find in the cloud, for example. How secure is that client against hacking, or against unauthorized remote configuration? If the SD-WAN provider can remotely manage the endpoint hardware or software, perhaps a hacker will be able to break in. Ask how well protected is that endpoint against a rogue employee at the SD-WAN provider, or the provider itself being hacked. Expect good answers to those questions, and others regarding the service provider's security practices.
2. Are you securing SD-WAN endpoints to the cloud, in the enterprise data center, or both?
This makes a huge difference. In my experience, SD-WAN excels at tying small and remote offices to cloud service providers, whether software-as-a-service (SaaS) or infrastructure or platform-as-a-service (IaaS or PaaS). Many cloud providers already support secure endpoint clients for the major SD-WAN services, just as they do for MPLS. When it comes to bringing traffic back to the enterprise data center, some solutions are pretty weak -- and only talk about their encryption strength. Be sure to research your specific use cases, and determine how well they tie into your overall WAN security requirements.
3. How much of SD-WAN security do you want to manage?
SD-WAN solutions are available just about any way you want them. If you want a turnkey solution, where the service provider handles everything for you, including provisioning raw bandwidth, setting up new endpoints, optimizing performance through compression, installing fault-tolerance, and managing security, that's available. If your existing WAN and network teams would prefer to secure the SD-WAN themselves, including full management of all access control lists (ACLs), make sure that's an option right out of the box.
4. Does the SD-WAN play well with your existing ITOps and SecOps tools?
Let's say that a bad actor tries to break into your cloud host's SD-WAN endpoint. Will that register on your security incident and event management (SIEM) console? I hope so. What if there's a DDoS attack against your SD-WAN provider's authentication middleman service? That should raise an alert as well. Even if the SD-WAN is a fully managed service, you can't outsource security -- and that means full transparency on the part of the SD-WAN provider, and appropriate integration with your IT and security operations tools, including logs, reports, trend analysis, and predictive analytics. Don't settle for anything less. If possible, test the integration, and ask to see recent outage and security-incident reports before signing the contract.
SD-WAN is real, it's mature, and it's generally secure. But like with any technology, it's not one-size-fits-all, and it's up to you to make sure that you can trust it. Be sure you know what you need before signing that contract. And again, don't simply choose the one that has the most bits in its encryption algorithms. While impressive, that's arguably the least important bullet-point in SD-WAN security.
— Alan Zeichick is principal analyst at Camden Associates, a technology consultancy in Phoenix, Arizona, specializing in enterprise networking, cybersecurity, and software development. Follow him @zeichick.