A New Fence: The Software-Defined Perimeter

The network perimeter is dead: Long live the new perimeter! The boundary of your enterprise network can now be defined by software – but is that the right answer for your organization?

Patrick Foxhoven, CIO & VP of Emerging Technologies, Zscaler

October 31, 2017

4 Min Read

In today's digital environment, the user experience is everything. Thanks to the anytime/anywhere access they've come to expect from consumer apps on tablets and smartphones, workers want the same no-fuss experience in their business applications. They don't want anything to change because they're out of the office or using a phone, compared to being at their desks.

Add in the need for speed, and you can see why businesses are embracing the flexibility and agility of the cloud. But with more and more applications moving off the corporate network, and more employees working remotely, you're faced with a challenge: the systems designed to securely connect those users to their apps are ineffective in the cloud. In fact, they're practically irrelevant.

Let's look at how businesses offer secure remote access. Whether your apps are in the data center or cloud, users access them using 20-year-old virtual private network (VPN) technology. (VPNs were never meant to connect users to applications –- they were intended to connect networks to networks.) The problem is that bringing users from a remote network (via the Internet) onto a trusted or secure network just to access an application within is inefficient at best, and risky at worst.

If you grant outside users access to your network by way of a VPN, you are significantly broadening your attack surface and elevating risk. A partner or employee whose system has been compromised can infect your network, and malware can then move laterally, scanning for other resources and other vulnerabilities to exploit.

For example, we've all seen what happens when a remote user is compromised and they connect back to a network that has lateral access to a credit card payment processing environment or can communicate with sensitive back end financial systems. These types of breaches can, and have, put companies in the headlines and cost them fortunes.

In addition, many companies use a VPN to secure access to applications that are not even in the data center; instead, they've migrated to an infrastructure-as-a-service (IaaS) provider like AWS or Azure. To make this access possible, traditional VPNs require painful, hairpin-type traffic routing that moves traffic from the user to the corporate data center where the VPN concentrator is and out via another VPN to the IaaS provider before making its return trip back to the user. It's a slow and miserable experience for the user, an ongoing challenge for the administrator, and an expensive piece of technology that raises security concerns of its own.

Traditional VPNs are laborious, requiring users to take different actions depending on where they are and what applications they are accessing. Some examples are:

  • When outside the office, users must connect to a VPN before attempting access to applications, but when inside the office there's no need to connect.

  • Or, a user may attempt to access an application from a tablet, but is denied because there is no VPN client configured on the device.

  • Then there is the issue of a network that they are connecting from simply not supporting the communication requirements (ports and protocols) for a corporate VPN.

  • Sometimes the VPN doesn't work.

  • Sometimes users just need more. A very common scenario is clicking on a link within a corporate email account only to have the page that was attempted to load not work because they aren't on the corporate network and it's not something that is exposed externally.

Defining the perimeter differently
It's no longer enough to create a secure perimeter around your network assets. You need to flip the security model, basing it not on the location of the network but on policies tied to the user and application. This approach lets you provide fast, secure and efficient access that connects the right user to the right app, so you're not exposing your network and internal users to risk. With direct access to the applications needed, you're also providing a far superior user experience.

We can no longer risk the security of our networks by using outdated, inefficient and ineffective methods that don't adapt to new technological realities. Software-defined perimeters (SDP) offer a way of keeping networks safe and agile, while keeping employees satisfied and productive and helping you meet desired business outcomes.

Please join us for the remainder of this series on the software-defined network. In the following weeks, we'll offer insights on application "invisibility," using the Internet as a secure network and application segmentation without network segmentation. (For more insights on the SDP approach, check out the Cloud Security Alliance's SDP Security Model.)

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— Patrick Foxhoven is CIO and VP of Emerging Technologies at Zscaler.

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About the Author(s)

Patrick Foxhoven

CIO & VP of Emerging Technologies, Zscaler

Patrick Foxhoven is an experienced and innovative managed security entrepreneur and technologist, having spent 20 years building secure and scalable Internet-enabled networks while co-authoring three books on information security and receiving multiple patents. He is currently Chief Information Officer & Vice President of Emerging Technologies at Zscaler.

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Prior to joining Zscaler in 2010, he was a founder and CIO of CentraComm, a leading managed IT security and services provider, and served earlier as an owner and principal network engineer of Friendly Net, an early residential ISP in the midwest United States.

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