What is Zero Trust?
Since mobile users began connecting via unmanaged devices to business applications over the internet, there’s been growing need for zero trust approach. When you can’t trust the connection, device, or network, zero trust sounds like a great idea. But in the last few years, there’s been a lot of confusion about what the term actually means.
At its core, the concept is simple: zero trust = assume everything to be hostile. While this sounds obvious, the notion is antithetical to the network security model. Since the early 1990s, companies have been surrounding their networks with perimeter security and using endpoint-based controls, relying on approved IP addresses, ports, and protocols to validate applications, data, and/or users, which are then trusted to communicate inside the network.
In contrast, the zero trust approach treats all traffic, including traffic already inside the perimeter, as hostile. Unless workloads have been identified by a set of attributes—a workload fingerprint or identity—they are untrusted and blocked from communicating. Identity-based policies result in stronger security that travels with the workload wherever it communicates—in a public cloud, a hybrid environment, a container, or an on-premises network architecture. Because protection is environment-agnostic, applications and services are secured even if they communicate across network environments, requiring no architectural changes or policy updates.
A key aspect of zero trust is least-privileged access, which means it eliminates the excessive trust users have once inside a traditional network. With a zero trust approach, least-privilege is not only applied to access requests, but also to what—which services, devices, or connections—where, and when, which greatly reduces attack surfaces, giving defenders a narrower scope of focus.
The myth of zero trust security
Zero trust security is a term commonly used—and usually misused—in the security industry to describe the concept of network protection enabled by an implemented zero trust security model. But zero trust actually moves security off the network, focusing instead on protecting users, applications, and workloads.
Zero trust is based on four principles:
- Least-privileged access with all entities (users, devices, and workloads) continually re-authenticated and re-authorized based on context
- Microsegmentation at the application level without network segmentation
- Applications and network remain invisible to the open internet
- The internet becomes the new transport network via encrypted microtunnels
Why adopt a zero trust approach?
Today’s networks are hostile places. They host business-critical data, apps, and services, making them ripe for attack by cybercriminals who would like nothing more than to steal, destroy, or hold hostage sensitive data, such as personally identifiable information (PII), intellectual property (IP), and financial information for personal gain.
While no security is perfect, and data breaches will never be totally eliminated, zero trust reduces the attack surface and limits the blast radius—that is, the impact and severity—of a cyberattack, which reduces the time and cost of responding to and cleaning up after a breach.
Four benefits of zero trust
1. Reduces business and organizational risk
Zero trust assumes all applications and services are malicious and are disallowed from communicating until they can be positively verified by their identity attributes—immutable properties of the software or services themselves that meet predefined authentication and authorization requirements.
Zero trust, therefore, reduces risk because it uncovers what’s on the network and how those assets are communicating. Further, as baselines are created, a zero trust model reduces risk by eliminating overprovisioned software and services and continuously checking the “credentials” of every communicating asset.
2. Provides control over cloud and container environments
Security practitioners’ greatest fears about moving to and using the cloud are loss of visibility and access control. Despite an evolution in cloud service provider (CSP) security, workload security remains a shared responsibility between the CSP and the organization using the cloud. That said, there is only so much an organization can affect inside someone else’s cloud.
With zero trust, security policies are based on the identity of communicating workloads and are tied directly to the workload itself. In this way, security stays as close as possible to the assets that require protection and is not affected by network constructs such as IP addresses, ports, and protocols. As a result, protection not only travels with the workload where it tries to communicate but remains unchanged even as the environment changes.
3. Helps reduce the risk of a breach
Because the zero trust model is focused on the workload, it’s easier for security teams to identify and stop malicious data-based activity. A zero trust approach always verifies, preventing workloads that are unverified from communicating anywhere on the system—to and from command-and-control, and between hosts, users, or applications and data (and any combination thereof).
Any altered application or service, whether it’s a result of adversarial activity, misuse, or accident, is automatically untrusted until it can be verified again through a set of policies and controls. Even when verified and approved, communication is restricted to a “need-to-know” basis; in other words, secure access is locked down to only the users, hosts, or services that need it.
4. Supports compliance initiatives
With zero trust, auditors (and others) achieve clearer insight into what data flows the organization has and can see how workloads are protected. Zero trust mitigates the number of places and ways network communications can be exploited, resulting in fewer negative audit findings and simpler remediation.
In addition, with zero trust segmentation implemented, organizations have the ability to create perimeters around certain types of sensitive data (e.g., PCI or credit card data, data backups) using fine-grained controls that keep regulated data separate from other, non-regulated data. When it comes time for an audit, or in the event of a data breach, a zero trust segmentation strategy provides superior visibility and control over flat network architectures that provide over-privileged access.
Getting started with zero trust
It’s important to recognize that zero trust is a strategy, not a single technology or even a process. Designing for zero trust requires security and IT teams to focus on business concepts: What are we trying to protect? From whom? Recognize that zero trust underpins the entire security program; technologies and processes are layered on top of the strategy, not the other way around.
Zero trust can be delivered as a service, which is recommended by Gartner in its zero trust network access (ZTNA) framework. It can also be implemented in stages, with organizations starting with their most critical assets. As an alternative, they can start with non-critical assets as a test case before implementing zero trust more broadly. Regardless of your starting point, a zero trust approach returns immediate gains through risk reduction and security control.