Establishing the Critical Value of Secure SD-WAN

By Nirav Shah | October 15, 2021

Business-critical, cloud-based applications and tools have enabled the growth of distributed organizations. But while these cloud-based applications and services meet organizational needs, they also place great demands on legacy wide-area network (WAN) infrastructures. Further, they stretch these legacy technologies to their limits as users expect high-quality experiences. To meet these demands, many organizations have been forced to move away from performance-inhibited WANs and instead adopt software-defined WAN (SD-WAN) architectures. 

The Rise of SD-WAN and Remote Work

In recent years, many organizations have moved towards SD-WAN. This is primarily due to the benefits this technology offers, including the ability to:  

  • Close the skills gap facing IT organizations
  • Increase network agility
  • Improve visibility into network and applications

However, when organizations were required to rapidly adopt fully remote work models in 2020, reliable access to critical resources became imperative. This is where SD-WAN and Zero Trust Network Access (ZTNA) architectures rose in significance – they make business continuity and user productivity in a rapidly changing world possible.

Modern businesses run on applications, making SD-WAN a critical solution. SD-WAN enhances branch networking so that organizations can maintain the expected user experience, no matter a person’s geographic location. For Software-as-a-Service (SaaS) and Unified-Communications-as-a-Service (UCaas) applications, SD-WAN enhances branch networking with:

  • Significant simplification
  • Improved application performance
  • Faster cloud on-ramping
  • Monitoring and modify connections
  • Reduced latency, jitter, and packet loss

It also provides capabilities that enable high-bandwidth applications and services like digital voice and video. Moreover, the global SD-WAN market is expected to grow to $8.4 billion by 2025 – a CAGR of 34.5% - mainly because of its benefits. 

Limitations of Legacy SD-WAN

Despite the way SD-WAN revolutionizes branch connectivity and user experience, CISOs should be aware of the various security challenges that come with traditional, unsecured models.

Lack of Visibility

SD-WAN’s dynamic nature ensures consistent monitoring, correcting, replacing, and restoring of connections. This is how it maintains optimal application performance. Unfortunately, many security solutions used with SD-WAN struggle to keep pace with these changes. Moreover, since many solutions cannot fully integrate into the organization’s security strategy, tracking applications and workflows end-to-end becomes impossible. With a non-integrated SD-WAN security overlay approach, organizations often have short-term protection gaps that cybercriminals can target and exploit. 


Managing SD-WAN architectures also poses a challenge, especially as IT departments look to troubleshoot across multiple branches – cloud-to-cloud, cloud-to-data center, and remote work only make this more challenging. Because of these challenges, organizations need SD-WAN that can support various use cases while also integrating across the networking, connectivity, and security functions. Further, it must be done within a single, centralized management console. Otherwise, enforcing security policies consistently across all use cases while maintaining centralized control of the SD-WAN infrastructure will burden already limited IT staff. This again leads to defensive gaps that threat actors can exploit. 

VPN reliance

The over-reliance on just virtual private networks (VPNs) can lead to security risks. Cybercriminals target older, unpatched, consumer-grade home-network devices so that they can exploit vulnerabilities in them. They look to ultimately gain access to the corporate network. 

Organizations relying on legacy SD-WAN face the same problem. Branch offices gain flexible and reliable application access, but the connections lack the protections typically employed within the corporate network. As a result, organizations can only protect their branch offices with little more than a VPN, exposing the enterprise to new security risks. 

Minimal Security

CISOs must provide their branch offices with a full suite of enterprise-grade protection that adapts to SD-WAN’s dynamic nature. To do this, many seek SD-WAN solutions that include a full range of proven and validated security tools. 

However, effective SD-WAN implementations must secure various connections across the enterprise infrastructure. The security solution must be able to inspect high traffic volumes at a speed that parallels the applications, and it needs to do this without inhibiting network performance. Unfortunately, few legacy SD-WANs provide this, undermining the security goals that the organization has set. 

Inability to Inspect Encrypted Traffic

To secure these connections, SD-WAN solutions must be able to inspect encrypted traffic like secure sockets layer (SSL)/transport layer security (TLS). These now make up approximately 85% of network traffic.

However, many SD-WAN solutions lack these capabilities. As cybercriminals leverage encryption to infiltrate networks and exfiltrate data, organizations increase their data breach risks by leaving this traffic uninspected. Even more concerning, most firewalls cannot inspect encrypted traffic, undermining the organization’s security postures. Those looking to secure these connections must purchase additional appliances to inspect encrypted traffic at the edge of the network. 

Secure SD-WAN with Integrated ZTNA 

Most SD-WAN solutions do not have security built into them. Without integrated security, direct internet access increases the organization’s risk and leaves it vulnerable to new threats. To address these threats effectively, SD-WAN must contain a full suite of enterprise-grade security solutions, including security and networking functions that operate as a unified system. Known as security-driven networking, this approach ensures security seamlessly adapts to and scales with the SD-WAN connectivity. In doing this, the organization prevents the security gaps that the overlay security approach creates. 

Moreover, organizations should adopt a ZTNA model that encrypts access to applications while enforcing verification and application access controls for users and devices. Unlike VPNs, ZTNA can hide applications from the internet, reducing the potential attack surface. Enhancing critical security functions with AI and custom-built processors that accelerate encrypted traffic inspection means organizations never have to sacrifice performance. 

Consolidating SD-WAN, next-generation firewalls (NGFW), advanced routing, and access proxy within a Secure SD-WAN solution enables ZTNA, helping to achieve secure, distributed digital business models. In doing this, organizations protect and enable work-from-anywhere business models where employees can connect to the networks on any device. This seamless security maintains productivity and continuity so that the company can attract and retain top talent. In the end, organizations can exceed customer expectations, increasing overall revenue. 

For CISOs to help their organizations compete effectively in today’s digital marketplace, Secure SD-WAN can no longer be seen as a nice-to-have – it must be seen as a necessity.