Build your Cyber Security Career Part — 2

Zero Trust versus Trust but Verify

Trust is a very complex topic; in reality, we cannot function without trust. If one were to think that the laptop vendor has installed spyware on the laptop, they would most likely end up rebuilding the system. If one were to mistrust the hardware vendor, they would stop using it completely. If we think of trust on a business level, things only become more sophisticated; however, we need some guiding security principles. Two security principles that are of interest to us regarding trust:

• Trust but Verify
• Zero Trust

Trust but Verify: This principle teaches that we should always verify even when we trust an entity and its behaviour. An entity might be a user or a system. Verifying usually requires setting up proper logging mechanisms; verifying indicates going through the logs to ensure everything is normal. In reality, it is not feasible to verify everything; just think of the work it takes to review all the actions taken by a single entity, such as Internet pages browsed by a single user. This requires automated security mechanisms, such as proxy, intrusion detection, and intrusion prevention systems.

Zero Trust: This principle treats trust as a vulnerability, and consequently, it caters to insider-related threats. After considering trust as a vulnerability, zero trust tries to eliminate it. It is teaching indirectly, "never trust, always verify." In other words, every entity is considered adversarial until proven otherwise. Zero trust does not grant trust to a device based on its location or ownership. This approach contrasts with older models that would trust internal networks or enterprise-owned devices. Authentication and authorization are required before accessing any resource. As a result, if any breach occurs, the damage would be more contained if a zero trust architecture had been implemented.

Microsegmentation is one of the implementations used for Zero Trust. It refers to the design where a network segment can be as small as a single host. Moreover, communication between segments requires authentication, access control list checks, and other security requirements.

There is a limit to how much we can apply zero trust without negatively impacting a business; however, this does not mean that we should not apply it as long as it is feasible.

There are three terms that we need to take note of to avoid any confusion.

• Vulnerability: Vulnerable means susceptible to attack or damage. In information security, a vulnerability is a weakness.
• Threat: A threat is a potential danger associated with this weakness or vulnerability.
• Risk: The risk is concerned with the likelihood of a threat actor exploiting a vulnerability and the consequent impact on the business.

Away from information systems, a showroom with doors and windows made of standard glass suffers a weakness, or vulnerability, due to the nature of glass. Consequently, there is a threat that the glass doors and windows can be broken. The showroom owners should contemplate the risk, i.e. the likelihood that a glass door or window gets broken and the resulting impact on the business.

Consider another example directly related to information systems. You work for a hospital that uses a particular database system to store all the medical records. One day, you are following the latest security news, and you learn that the used database system is not only vulnerable but also a proof-of-concept working exploit code has been released; the released exploit code indicates that the threat is real. With this knowledge, you must consider the resulting risk and decide the next steps.