Is SDN your next security nightmare?

Software-defined networking offers many positives, but keep an eye on possible vulnerabilities

San Francisco -- The big buzzword in networking these days is Software-Defined Networking (SDN),  a de-coupling of the data plane and the control plane that allows you to manage physical devices via a software-based controller sitting on a general purpose server.

There are numerous benefits associated with SDN. Instead of having to touch every switch and router, the controller enforces policies by using the OpenFlow standard to talk to the physical networking devices. Also, customers can theoretically use any OpenFlow enabled hardware, meaning you no longer have to buy all of your networking gear from the same vendor.

But before you jump into SDN, be aware that there might be some security risks. That’s the view of Robert Hinden, an industry veteran and Check Point Fellow, who spoke this week at the RSA Conference.

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Hinden points out that once you’ve established centralized control of your network on this server, what happens if that server is attacked? What if a hacker gains control of the SDN controller?

Theoretically, the hacker could direct traffic around your firewalls, insert malware into the network, run man-in-the-middle attacks or send traffic to compromised nodes.

Also, what happens when outages or bugs occur in the network? It’s unclear today how the SDN controller would deal with network outages that might require the re-routing of traffic, Hinden says.

In addition to security concerns, Hinden questioned how well SDN can scale. He pointed out that traditional routing and switching is destination based, with the physical devices reading headers and using routing tables to send packets to the appropriate destination.

But SDN is flow-based, which is good because it allows network managers to create fine-grained policies. On the other hand, all of those flow entries must be sent out to all of the devices on the network. Hinden worries that this could get unwieldy.

On the other hand, Hinden sees some positives when it comes to SDN and security. The controller can push security policies to all routers and switches on the network, creating a uniform SDN security posture for all traffic.

Also, if there is a compromised host, for example, the controller can easily isolate that host from the rest of the network, he says.

While it’s still very early in the SDN adoption cycle, Hinden recommends that networking teams and security teams begin working together, because in an SDN world, “all network staff will be responsible for security.”

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