Despite never-ending data breaches and ransomware attacks, too many companies still rely on the outdated "trust but verify" cybersecurity strategy. This approach assumes that any user or device inside a company's network can be trusted once it has been verified. The approach has clear weaknesses: Many businesses are putting themselves at additional risk by verifying once, then trusting forever.

There was a time when trust but verify made sense, namely when networks were self-contained and well-defined. But at some point, perhaps due to the overwhelming volume of devices on a network, the number of patches needing to be applied, user demands, and resource constraints in the cybersecurity team, things began to slip. Initial verification meant the asset was trusted, but no additional verification ever took place.

It's easy to see how this happens with users. A user typically goes through a background check when they join the company, but once onboarded, despite any number of changes in their lives that could affect their trustworthiness, we allow them to access our systems and data without further verification.

In the majority of cases, the absence of further verification does not cause damage. However, if the user decides to act against the best interest of their employer, the results can be catastrophic. The more sensitive the information the individual has access to, the greater the risk. This is why individuals with security clearances are regularly re-vetted, and security personnel may conduct regular finance checks to identify any issues early and intervene to mitigate possible damage.

In organizations that follow a trust-but-verify approach, two personas stand out: those that have considered the risk of one-time asset verification acceptable; and -- the minority -- those that try to manage the risk with a re-verification program. A shift in persona from the former to the latter usually only occurs after a breach, a crisis in availability, or another "career limiting disaster."

The reality is that there are simply not enough hours in the day for security practitioners to do all of the things that must be done. Have security patches been correctly applied to all vulnerable devices? Are all third-party security assessments properly analyzed? Do all Internet of Things (IoT) devices really belong on the network? Are managed security services performing as expected?

Compromising one of these trusted devices means being granted trust to move laterally across the network, accessing sensitive data and critical systems. Organizations likely will not know the extent of their exposure until something goes wrong.

When these breaches are eventually discovered, the costs begin to mount. Companies face not only the direct costs of incident response, but potentially also regulatory fines, class-action lawsuits, lost customers, and lasting damage to their brand reputation. Relatively small incidents can cost millions of dollars, while large incidents regularly cost billions.

In addition to these direct costs, insufficient verification also leads to more frequent and expensive compliance audits. Regulators and industry bodies are increasingly demanding that companies demonstrate robust identity and access management controls, for example under the European Union's upcoming Digital Operational Resilience Act (DORA), as well as continuous monitoring and validation of user and device activity. Certifications and accreditations can no longer be accepted at face value.

Instead of trusting after verification, businesses should instead allow only what the business needs, for as long as it needs it. Never trust, always verify. This is how a zero-trust architecture operates.

Every user, device, and application that attempts to make a connection, regardless of its location, is scrutinized and validated, dramatically limiting the potential damage from a successful compromise. A zero-trust architecture replaces firewalls and VPNs, so there are fewer devices to maintain, and a reduced attack surface means fewer opportunities for attackers to gain a foothold.

Zero trust doesn't mean zero testing; testing should form an integral part of any IT and cybersecurity strategy. However, it does mean the likelihood of a major failure stemming from trust being extended to users, devices, or applications that do not deserve it, is a thing of the past.