Access Controls: What They are and How to Implement Them

Controlling who can access your systems, spaces, or data is no longer just an administrative measure—it’s one of the pillars that defines the security of any company. Every day, organizations of all sizes face unauthorized access attempts, human errors, and breaches that could be prevented with the right approach.

At TecnetOne, we’ve prepared this guide to help you understand why access controls are essential and how to implement them properly. The goal is to help you make informed decisions, strengthen your security strategy, and protect what truly matters within your organization.

What Is Access Control?

The term “access control” refers to the set of rules, processes, technologies, and policies that determine who can enter, view, or use a resource—whether physical (an office, a server room) or digital (a database, a cloud system). In other words, access control defines which users can access which resources, when, and under what conditions.

When implemented correctly, access control becomes a fundamental part of your security strategy, as it limits the scope of potential damage and reduces your company’s attack surface.

This concept also goes hand in hand with identity and access management (IAM), as its purpose is to ensure that only the right people gain access to the right resources. In other words, it’s about granting permissions to users who have already been authenticated and authorized, while blocking any access attempts from those who shouldn’t see sensitive information or use certain systems.

That’s why any security system with access controls must verify who the user is and what permission level they have before granting access to a physical area or internal data. It’s the most effective way to keep things in order and avoid unnecessary risks.

Why Are Access Controls Important?

Implementing a robust access control system isn’t just a “nice-to-have”—it’s a necessity if you want to protect your company from internal and external threats. The main benefits include:

1. Protection Against Unauthorized Access: If anyone could freely access critical systems, databases, or sensitive physical areas, the risk of breaches would increase dramatically. A proper access control system prevents unauthorized users from obtaining confidential data or performing actions beyond their roles.

2. Compliance with Regulations and Standards: Many information security standards (like ISO 27001, PCI DSS, GDPR) require detailed record-keeping, defined roles, and controlled access to sensitive data. A well-designed access control system helps you meet legal and contractual requirements.

3. Improved Traceability and Incident Response: When a user accesses a resource, the system logs the action. If an incident occurs (e.g., suspicious access), you’ll have visibility into the “who, when, what,” allowing for investigation or incident reconstruction, and faster response times.

4. Operational Organization and Efficiency: By defining roles, profiles, and permissions, each team member gets exactly the access they need to do their job. This reduces human error, boosts efficiency, and strengthens the security culture.

5. Adaptation to Hybrid and Remote Work Environments: In settings where employees work remotely or in hybrid models, access control becomes even more crucial. It ensures that remote users only access the resources they need—and that such access is secure and auditable.

For all these reasons, having a strong access control system is a central component of any security strategy.

Phases of Access Control

While it’s common to hear that access control is based on three principles (identification, authorization, and authentication), the reality is that a modern, well-implemented system goes far beyond that. Today, to ensure truly strong security, additional phases are needed to complete the cycle.

Identification

Everything starts with creating the user’s digital identity. This is where the user is registered in the system and assigned the data that will allow for recognition: username and password, fingerprint, facial recognition, or any other method that turns their identity into something technology can unmistakably validate.

Authorization

Once the user exists in the system, the key question arises: what exactly can they access? This phase is based on internal policies and the type of access control the company has defined. Authorization is not the same for everyone—it depends on the user’s role.

For example, only the finance team should be able to access the economic transaction databases. It’s essentially about setting clear boundaries: who can see what, and under what conditions.

Authentication

This is where the system confirms that the person trying to gain access is truly who they claim to be. There are different credentials used in this step:

1. Username and password

2. Biometric systems (fingerprint, face, voice, retina)

3. Digital signatures or certificates

If this verification is successful, the user proceeds to the next level.

Access

After validating identity and permissions, the system finally grants access. This is the moment when “the door opens,” and the user is allowed to enter only the resources or areas they are authorized to access—no more, no less.

Management

Every good access control system requires constant administration. This includes tasks such as:

1. Onboarding new users

2. Removing access for former employees (offboarding)

3. Adjusting permissions according to role changes

4. Detecting and fixing vulnerabilities

Without active management, any security system eventually loses its effectiveness.

Audit

Finally, there’s the phase that keeps everything organized: auditing. Every change made (what was changed, who made it, and when) must be perfectly logged. This helps to:

1. Verify that access settings are correctly configured

2. Investigate incidents or unusual access attempts

3. Comply with data protection regulations, especially when handling sensitive data like medical records or financial information

Having a reliable audit trail is key to reducing risks and demonstrating compliance during any security review.

Read more: NIS2 vs DORA: Key Differences Between the European Regulations

Types of Access Control

Security systems don’t work the same for every company, which is why there are different types of access control. Each model defines its rules based on how access to information and internal resources is granted or restricted. Here are the four most common models, explained with clear examples to make them easy to understand.

Discretionary Access Control (DAC)

The DAC model is one of the most widely used, especially in traditional operating systems. In this model, the resource owner (a file, folder, or system) decides who can access it and with what permissions.

The advantage is flexibility. The downside… is also flexibility. That flexibility can turn into a risk, as users with high privileges might gain access to data they don’t really need. For example, a marketing manager might access financial information that should only be visible to the finance department—simply due to their level of access.

Mandatory Access Control (MAC)

The MAC model is the “heavyweight” of security. It’s mostly used in military, government, or other environments where data is highly sensitive.

Here, the resource owner doesn’t decide—an authoritative entity defines security levels for everything. Every document, file, or system is classified (e.g., public, confidential, classified), and every user has a clearance level. Access is only allowed if the user’s level matches or exceeds the required one.

It’s the most secure model, but also the most rigid. Proper implementation requires careful planning.

Role-Based Access Control (RBAC)

RBAC is the go-to model for modern businesses. Instead of assigning permissions to individual users, permissions are assigned to roles (e.g., Accounting, Marketing, IT, HR). Then, each employee is assigned a role based on their function.

This keeps things organized: accounting can’t see IT data, and IT doesn’t need access to financial reports. It’s practical, scalable, and easy to maintain when employees change roles.

Attribute-Based Access Control (ABAC)

ABAC takes flexibility to the next level. Here, it’s not just about who you are or what your role is—it’s also about the context in which you’re trying to access something. Factors like location, time, device type, or risk level affect the access decision.

For example, a user may be allowed to access a system from the office but not from a different country or outside business hours.

ABAC enables highly detailed and personalized rules, reducing the need for static roles and offering more dynamic, adaptive control.

Common Mistakes When Implementing Access Control

Despite good intentions, many companies make mistakes that weaken their security systems. Here are some to avoid:

1. Granting unlimited access to users “for convenience” or “because they’re trusted.” This breaks the principle of least privilege.

2. Failing to review permissions when users change roles or leave the company, leaving obsolete accesses active.

3. Only using basic authentication (username/password) without additional factors, which makes impersonation easier.

4. Not keeping or reviewing logs—without auditing, unauthorized access can go unnoticed.

5. Choosing an unsuitable model for the organization (e.g., using DAC in a highly regulated environment), weakening security.

6. Not training staff—technology alone isn’t enough; users remain the weakest link.

7. Ignoring integration with the broader security strategy—access control should align with identity management, monitoring, backups, and incident response.

Conclusion

Access control is essential to protect your company’s information and prevent it from falling into the wrong hands. It not only blocks unauthorized access but also allows you to audit who accessed what and when—helping detect issues and fix vulnerabilities. It also improves internal organization by defining roles and permissions, which is especially useful in remote and cloud environments.

At TecnetOne, we understand that implementing and managing access control can be a challenge. That’s why we help companies like yours define policies, adjust permissions, and strengthen their security. If you need support improving your access controls, schedule a consultation with our team—we’ll walk you through it step by step.