What Is a Zero Trust Policy?
A Zero Trust policy is a cybersecurity approach that requires continuous verification of every user and device, replacing traditional perimeter-based trust models with "never trust, always verify". Every access request must be verified before access is granted, regardless of whether the request comes from inside or outside the corporate network.
These policies typically evaluate factors such as user identity, device security, location, requested resource, and current risk level. They also enforce least-privilege access, so users receive only the permissions they need. Access can be checked continuously, allowing an organization to block or restrict a session when conditions change.
In this article:
- What Is the Purpose of a Zero Trust Policy?
- What Should a Zero Trust Policy Include?
- How to Create a Zero Trust Policy
- How to Enforce a Zero Trust Policy
What Is the Purpose of a Zero Trust Policy?
Eliminate Implicit Trust
Zero Trust policies require verification for each access request. Being connected to an internal network, using a company device, or having authenticated earlier does not automatically grant continued access. Trust must be established from current identity, device, and risk signals.
This approach reduces reliance on network location as a security boundary. If an attacker compromises an internal account or device, they should not automatically gain broad access to other systems. Each request is evaluated independently, which helps limit lateral movement.
Related content: Read our article about Zero Trust security in your organization
Standardize Access Decisions
A documented policy gives teams a common set of rules for evaluating access. It can define required authentication methods, acceptable device conditions, access restrictions, and when additional verification is needed. This reduces inconsistent decisions between systems and administrators.
Standardization also makes access controls easier to implement across different environments, including cloud services, on-premises systems, and remote access tools. Teams can apply the same decision criteria instead of creating separate rules for every application.
Reduce Excessive Privileges
Zero Trust policies support least-privilege access by limiting users and services to the permissions required for a specific task. They can also require temporary or conditional access instead of permanent elevated privileges, reducing the impact of compromised accounts.
Policies can define when privileged access should expire, require additional approval for sensitive actions, or restrict administrative access to specific devices. Regular access reviews can also identify permissions that are no longer needed.
Define Accountability for Access Control
A Zero Trust policy clarifies who can approve access, who maintains access rules, and who reviews exceptions. It also establishes requirements for logging and periodic access reviews, making it easier to identify inappropriate permissions and determine how access was granted.
Clear ownership is important when access rules span multiple teams, such as security, IT, application owners, and compliance. Defining responsibilities helps ensure exceptions are reviewed, outdated permissions are removed, and access decisions can be traced during audits or incident investigations.
What Should a Zero Trust Policy Include?
A Zero Trust policy should define the rules used to evaluate and control access across users, devices, applications, and networks. It should be specific enough for security and IT teams to implement consistently, while also defining who owns each part of the access control process.
Policy Scope
The policy should state which users, devices, applications, networks, and data it covers. It should also define whether the rules apply to employees, contractors, third parties, service accounts, remote users, and cloud environments. Clear scope prevents gaps between systems. It also helps teams understand where Zero Trust controls are mandatory and where separate policies may apply.
Roles and Responsibilities
The policy should identify who is responsible for defining, approving, implementing, and reviewing access controls. Typical roles include security teams, IT administrators, application owners, managers, and compliance teams. It should also define who can approve exceptions and who is responsible for removing outdated access. Clear ownership reduces delays and avoids situations where permissions remain active because no team is accountable for them.
Identity Verification Requirements
The policy should define how users and services must prove their identity before receiving access. This can include password requirements, single sign-on, certificate-based authentication, hardware-backed credentials, or identity provider checks. Verification requirements should reflect the sensitivity of the requested resource. Higher-risk access may require stronger authentication or additional validation before access is granted.
Multi-Factor Authentication Requirements
The policy should specify when multi-factor authentication is required and which authentication factors are acceptable. MFA is commonly required for remote access, privileged accounts, sensitive applications, and administrative actions. The policy can also define stronger MFA methods for higher-risk scenarios. For example, phishing-resistant methods such as security keys or passkeys may be required for privileged users.
Least-Privilege Access Rules
The policy should require users and services to receive only the permissions needed to perform their tasks. Access should be based on job responsibilities, application requirements, or specific business needs. It should also define how temporary and elevated access is handled. Permissions should expire when they are no longer needed instead of remaining active indefinitely.
Device Trust and Compliance Requirements
The policy should define the device conditions required for access. These may include supported operating systems, current security patches, disk encryption, endpoint protection, screen locking, and device management enrollment. Access can be restricted when a device does not meet these requirements. The policy should also explain how unmanaged or personal devices are treated.
Network and Application Access Rules
The policy should define how users and devices are allowed to connect to applications and network resources. Access decisions should be based on identity, device posture, requested resource, and risk rather than network location alone. Rules may also cover segmentation, application-level access, encrypted connections, and restrictions between sensitive environments. These controls help limit lateral movement if an account or device is compromised.
Privileged Access Requirements
The policy should apply stricter controls to administrative and other high-privilege accounts. This can include separate administrator accounts, stronger authentication, approval workflows, session logging, and time-limited access. Permanent privileged access should be minimized where possible. Just-in-time access can grant elevated permissions only for the duration of an approved task.
Related content: Read our article about privilege escalation
Third-Party and Contractor Access
The policy should define how external users receive access to internal systems and data. Third-party access should follow the same verification and least-privilege principles as employee access. The policy should define expiration dates, sponsorship requirements, approved devices, and access review procedures. Access should be removed promptly when a contract or business relationship ends.
Access Review and Recertification
The policy should require periodic reviews of user, service, and privileged access. Managers or resource owners should confirm that permissions are still required and appropriate. Review frequency can vary based on risk. Sensitive systems and privileged accounts may need more frequent recertification than standard business applications, and unnecessary access should be removed as part of the review process.
How to Create a Zero Trust Policy
Creating a Zero Trust policy starts with defining what needs protection, who needs access, and which conditions must be met before access is allowed. The policy should translate Zero Trust principles into rules that security, IT, and application teams can enforce consistently.
Step 1: Define the Policy Scope and Objectives
Start by defining which users, systems, applications, networks, devices, and data the policy covers. Include employees, contractors, service accounts, cloud resources, and remote access where relevant.
The objectives should explain what the policy is intended to achieve, such as:
- Reducing implicit trust
- Limiting excessive privileges
- Improving access visibility
- Protecting sensitive systems
Step 2: Identify Protected Resources and Access Paths
Create an inventory of the resources that require protection. This can include:
- Applications
- Databases
- Cloud services
- Administrative interfaces
- APIs
- Internal networks
- Sensitive data stores
Then document how users and workloads access those resources. Identifying access paths helps reveal where authentication, authorization, segmentation, or additional controls are needed.
Step 3: Classify Users, Devices, and Workloads
Group users, devices, and workloads according to their role, risk, and access requirements. For example, all these entities may require different controls:
- Administrators
- Standard employees
- Contractors
- Service accounts
- Managed devices
- Unmanaged devices
Classification makes it easier to apply consistent rules. High-risk identities or systems can be subject to stricter authentication and access requirements than lower-risk resources.
Step 4: Define Authentication and Identity Requirements
Specify how identities must be verified before access is granted. Requirements can include:
- Single sign-on
- Multi-factor authentication
- Phishing-resistant authentication
- Certificate-based authentication
- Stronger controls for privileged accounts
The policy should also define how authentication changes based on risk. Requests involving sensitive resources, unusual locations, or suspicious behavior may require additional verification.
Step 5: Establish Least-Privilege Access Rules
Define the minimum permissions users and workloads need to perform their tasks. Access should be tied to:
- Business roles
- Resource sensitivity
- Specific operational requirements
The policy should also address temporary and elevated access. Privileged permissions should expire when the task is complete instead of remaining assigned permanently.
Step 6: Define Device and Endpoint Requirements
Specify the security conditions devices must meet before they can access protected resources. Common requirements include:
- Supported operating systems
- Security patches
- Disk encryption
- Endpoint protection
- Device management enrollment
The policy should explain how noncompliant, unmanaged, or personal devices are handled. Depending on risk, they may receive limited access or be blocked entirely.
Step 7: Specify Continuous Monitoring Requirements
Define which signals should be monitored after access is granted. These can include:
- Login activity
- Device posture
- Session behavior
- Privilege changes
- Network activity
- Access to sensitive resources
Continuous monitoring allows access decisions to change when risk changes. A session can be restricted, reauthenticated, or terminated if suspicious activity or a compliance failure is detected.
Step 8: Define Access Review and Revocation Procedures
Set requirements for reviewing user, service, and privileged access on a regular basis. The policy should specify:
- Review frequency
- Responsible reviewers
- The types of access that require recertification
It should also define when access must be revoked, such as after role changes, employment termination, expired contracts, security incidents, or prolonged inactivity.
Step 9: Establish Exception and Approval Processes
Document how exceptions to the policy are requested, evaluated, approved, and tracked. Each exception should include:
- A business justification
- An owner
- An expiration date
- Any required compensating controls
Exceptions should not become permanent alternatives to the policy. They should be reviewed regularly and removed when the underlying need no longer exists.
Step 10: Document Enforcement and Review Responsibilities
Identify which teams and system owners are responsible for implementing and enforcing each part of the policy. This can include:
- Security teams
- Identity administrators
- Endpoint teams
- Application owners
- Managers
The policy should also define how often the policy itself is reviewed. Reviews should account for changes in infrastructure, business processes, threat patterns, and security controls so the requirements remain relevant.
How to Enforce a Zero Trust Policy
Identity and Access Management
Identity and access management systems provide the foundation for Zero Trust enforcement by controlling how users and services authenticate and what resources they can access. IAM platforms can centralize identity records, authentication methods, role assignments, and application access policies.
Organizations can integrate IAM with directories, HR systems, and application platforms to keep access aligned with employment status and job responsibilities. IAM can also enforce single sign-on, multi-factor authentication, and role-based or attribute-based access controls.
Identity lifecycle processes are especially important. New users should receive only required permissions, role changes should trigger access updates, and terminated accounts should be disabled quickly across connected systems.
Conditional Access
Conditional access evaluates the context of each access request before deciding whether to allow it. Signals can include user identity, device compliance, location, network, application sensitivity, authentication method, and detected risk.
Policies can respond differently depending on those signals. A low-risk request from a managed device may be allowed normally, while a request from an unknown device may require additional authentication or be blocked.
Conditional access should also be reevaluated when conditions change. For example, a device that becomes noncompliant or a session that shows unusual behavior can trigger reauthentication, restricted access, or session termination.
Privileged Access Management
Privileged access management controls accounts with administrative or other high-impact permissions. These accounts require stronger controls because compromise can give an attacker access to critical systems, security settings, or sensitive data.
PAM systems can require approvals, stronger authentication, credential rotation, session recording, and time-limited elevation. Administrative credentials can also be stored in secure vaults rather than shared or permanently assigned to users.
Just-in-time access further reduces risk by granting privileges only when a specific task requires them. After the approved period ends, the elevated permissions are automatically removed.
Endpoint and Device Management
Endpoint and device management tools enforce security requirements on laptops, desktops, mobile devices, and other endpoints. They can verify operating system versions, patch levels, disk encryption, endpoint protection, firewall status, and device management enrollment.
Device posture can then become part of the access decision. A compliant corporate device may receive full access, while an unmanaged or outdated device may be restricted to less sensitive applications.
Continuous compliance checks are also important because device security can change after login. If malware is detected, security software is disabled, or required patches are missing, access can be reduced or revoked.
Related content: Read our article about application control in modern enterprises
Network Access Controls
Network access controls restrict which resources users, devices, and workloads can communicate with. Instead of providing broad access after a connection enters the corporate network, Zero Trust limits communication to explicitly authorized systems and services.
Organizations can enforce these rules through network segmentation, microsegmentation, secure access gateways, software-defined access, application proxies, and firewall policies. These controls can separate sensitive workloads from general user traffic.
Restricting network paths also reduces lateral movement. If an account or endpoint is compromised, the attacker has fewer opportunities to reach unrelated applications, databases, or administrative services.
Automated Access Revocation
Automated access revocation removes or reduces access when predefined conditions are met. Common triggers include employee termination, role changes, expired contracts, inactive accounts, device noncompliance, detected threats, or the expiration of temporary privileges.
Automation can connect identity, HR, endpoint, security monitoring, and privileged access systems. When one system detects a relevant change, it can trigger access removal across multiple applications without waiting for manual action.
Organizations should also log revocation events and monitor whether removal succeeded. Failed revocations should generate alerts so administrators can address applications or accounts that remain accessible after access should have ended.
Enforcing a Zero Trust Policy on Endpoints with Airlock Digital
Airlock Digital helps organizations put Deny by Default principles into practice on their endpoints by enforcing strict control over what runs. Only trusted applications, scripts, and processes are allowed to execute, and everything else is blocked. This preventative approach stops unauthorized applications and threats before they execute, reduces reliance on reactive detection, minimizes the attack surface, and helps organizations maintain operational resilience across both IT and OT environments.
Key capabilities of Airlock Digital:
- Deny by Default execution control: Prevents the execution of all untrusted applications, ensuring only verified software runs on endpoints and that every endpoint operates under strict controls.
- Granular trust policies: Defines trusted applications at the file, path, publisher, or parent process level, giving teams precise control over what is allowed to run.
- Integrated threat intelligence: Uses real-time intelligence such as VirusTotal to block known malicious files and refine policies dynamically, with blocklisting available to supplement allowlisting.
- Simplified exception management: Securely allows temporary exceptions using One-Time Passwords (OTPs), maintaining control without compromising security.
- Comprehensive monitoring and reporting: Provides full visibility into endpoint activity through detailed logs, real-time alerts, and actionable reporting that helps teams identify and address policy violations immediately.
- Audit-ready compliance: Maintains detailed logs and reports that help organizations demonstrate adherence to regulatory requirements, including NIST, HIPAA, and PCI-DSS.
- Cross-environment support: Extends Deny by Default principles to legacy systems, operational technology, and hybrid environments with tailored policies.
- Security stack integration: Strengthens Deny by Default strategies through integration with existing security tools such as EDR, SIEM, and threat intelligence platforms.
Learn more about Deny by Default endpoint security with Airlock Digital.