The basic principles of Zero Trust
Introduction
What is Zero Trust – basic definition: an approach, not a product.
Zero Trust is a security strategy, not a “box” or a single system. Its essence is that trust is not assumed by default: every access attempt undergoes explicit verification (identity, context, device status), rights are limited by the principle of least privilege, and the architecture is built on the assumption of breach – “assume that compromise has already occurred” -to minimize the radius of damage and stop lateral movement. These principles are formulated by Microsoft in its Zero Trust guide.
Why the traditional “periphery + network trust” model is no longer effective.
Clouds and SaaS have blurred the perimeter
Resources and data are distributed between on-premises and multiple clouds, and the classic logic of “inside = secure” no longer applies. NIST explicitly points to a shift away from a static perimeter toward protecting users/resources, and Microsoft’s Zero Trust Guidance shows that security policies should be applied across all “pillars” -identity, devices, applications, data, network, and infrastructure.
Remote work and access “from any network”
Employees connect from cafes, homes, airports. Google’s BeyondCorp approach (practical implementation of zero trust) demonstrates a shift in access control from the perimeter to the user and device to enable secure “anywhere” working without a traditional VPN.
BYOD and the “zoo” of end devices
Smartphones, personal laptops, IoT, and partner devices greatly increase the attack surface. That is why one of the key pillars of the Microsoft model is Endpoints: checking the device’s “posture” (compliance, patches, security agents) becomes a prerequisite for access.
History and background
The emergence of the term and idea: why the need for “no trust by default” arose.
Although the term “Zero Trust” has not always been used literally, its conceptual roots date back to the early to mid-1990s, when researchers began to wonder: can devices or users within a network be trusted automatically? For example, Stephen Paul Marsh’s 1994 doctoral dissertation introduced the concept of “trust” as a computable concept.
However, the concept was popularized by John Kindervag of Forrester Research, who in 2010 formulated “Zero Trust” as a security model based on the idea: “Do not automatically trust any device or user, even if they are inside the perimeter.”
During the 2000s, there was a growing understanding that traditional network “walls” no longer provided adequate protection as infrastructure became distributed: clouds, mobile devices, partner connections. For example, the Jericho Forum concept referred to “de-perimeterisation” as a trend where the “network outside the perimeter” was becoming more important than the “network inside”.
The evolution of security architectures: from “castle and moat” (perimeter) to the “resource protection” model.
The traditional security model was often referred to as “castle-and-moat”: an organization builds a strong perimeter (firewall, DMZ, internal network) and considers everything inside the perimeter to be secure. The problem: once an attacker gets behind the “wall,” they gain almost complete access to resources because they are considered “trusted” within the network. This resulted in a large attack blast radius.
Over time, the following shifts have occurred:
· Network and resource segmentation: instead of “the entire network inside = secure,” it became “every resource is considered potentially vulnerable, every connection must be checked.”
· Micro-segmentation: networks are divided into small sections, access to which is controlled separately.
· Verification of devices, users, and services regardless of network location: the network boundary is no longer the main criterion for trust.
· The emergence of framework documents: for example, NIST SP 800-207 (published around 2020) formalized the principles of Zero Trust architecture, emphasizing that “the network can be compromised, so we must assume that trust by default is unacceptable.”
Key principles of Zero Trust
Never Trust, Always Verify
The main idea behind Zero Trust is to trust no one and nothing by default, even if the user or device is “inside the network.” Every request must be verified, regardless of its source.
Practice
Before granting access, the system checks:
· User identity (via MFA, SSO, tokens, etc.),
· Request context (location, time, device),
· Device status (antivirus, patches, corporate control),
· Risk (e.g., unusual behavior, new geography).
Example
An employee connects from their home Wi-Fi. Previously, VPN gave them “internal access.” Now Zero Trust requires them to pass MFA, ensure that their device complies with policies (up-to-date updates, disk encryption), and only then grants access to resources – and not all of them, but only those that are necessary.
Least Privilege Access
Access is granted only to the extent that is truly necessary for the user to perform their tasks.
Practice
· Minimize administrative rights.
· Divide users into roles (RBAC/ABAC).
· Apply Just-in-Time (JIT) access-grant elevated rights only temporarily.
· Automatically revoke unnecessary rights.
Example
An IT specialist must install an update on the server. The system grants him administrative rights for exactly 30 minutes. After completing the task, access is automatically revoked.
Assume Breach
Zero Trust assumes that compromise has already occurred and that action must be taken based on this assumption. This is not pessimism, but a mature approach: if an attack does occur, it is important to limit the damage and quickly detect the incident.
Practice
· Design architecture with isolation and microsegmentation.
· Collect and analyze telemetry in real time.
· Use EDR/XDR solutions for behavioral analysis.
· Ensure rapid response to incidents.
Example
The attacker gained access to one workstation. In a classic model, they could move freely across the network. In Zero Trust, each new access requires verification, and inter-segment connections are blocked by policies.
Context-Aware & Adaptive Access
Access decisions are made not only based on login and password, but also taking into account the context – who, where, on what device, and under what conditions is attempting to log in.
Practice
· Check geolocation, IP, time of day, behavior.
· Use risk-based authentication.
· Apply dynamic policies – if the context is safe, access is easier; if suspicious, MFA or blocking is required.
Example
A user usually logs in from Kiev, but suddenly logs in from Brazil. Zero Trust requires re-authentication or temporarily blocks access until verification.
Microsegmentation & Resource Protection
The network is divided into many small segments (zones), each with its own access policies. Even if one zone is compromised, an attacker will not be able to move freely throughout the entire network.
Practice
· Use cross-segment policies and controls.
· Restrict East-West traffic (internal connections).
· Apply solutions such as software-defined perimeter (SDP) and ZTNA.
Example
The HR department database is only accessible from HR application servers. Even if an attacker gains access to the marketing subnet, they will not be able to reach the HR database.
Architecture and implementation components
Overview of NIST SP 800-207 “Zero Trust Architecture”
What does NIST 800-207 define? The document formalizes Zero Trust as an approach where protection shifts from network zones to specific resources (assets, services, data), and access decisions are made dynamically based on policy and context.
Logical model of ZTA (simplified):
· Policy Decision Point (PDP):
· Policy Engine (PE): Determines whether access should be allowed or denied based on policies, context, and risk.
· Policy Administrator (PA): Enforces the engine’s decision – configures network controls, establishes sessions, or terminates them.
· Policy Enforcement Point (PEP) – Enforces access decisions at the resource boundary – it’s where control meets data flow (e.g., gateways, agents, proxies).
· Control Plane vs Data Plane: The control plane handles decision-making and communication between PE, PA, and PEP, while the data plane handles the actual resource transactions (traffic, data access).
Key NIST Principles
· Protect resources, not “the internal network.”
· Explicit verification for every connection.
· Least privilege and assume breach as default operational stances.
Deployment Models
Identity-Centric ZT
Based on IAM systems (SSO, MFA, conditional access). Policies live in identity platforms; PEPs are implemented as identity-aware proxies or agents.
Network-Centric ZT
Implemented through Software-Defined Perimeters (SDP) or ZTNA gateways that verify and isolate network connections.
Hybrid Model
Combines identity verification, device posture, and network segmentation for layered protection.
Alignment with CISA’s Zero Trust Maturity Model (ZTMM)
CISA divides ZT implementation into five pillars – Identity, Devices, Network, Applications/Workloads, Data – and four maturity levels:
Traditional → Initial → Advanced → Optimal.
Each level measures how deeply Zero Trust principles are integrated across systems and operations.
How to transition from your current infrastructure to ZT architecture: stages, challenges, recommendations.
Transitioning to Zero Trust is not a single project — it’s an iterative transformation. Below is a practical roadmap based on NIST SP 800-207 and CISA’s ZTMM.
Stage 0: Discovery & Goal Setting
Objective: Identify what you’re protecting and who interacts with it.
Actions:
· Inventory users, devices, applications, and data flows.
· Map “crown jewels” (most critical assets).
· Classify sensitivity and access paths.
Metrics: 95% asset visibility; documented ownership for critical systems.
Why: Zero Trust policies depend on knowing your environment precisely.
Stage 1: Establish Identity as the Foundation
Objective: Ensure every access request comes from a verified identity.
Actions:
· Implement SSO, MFA, and centralized IdP (e.g., Azure AD, Okta).
· Apply Just-In-Time (JIT) and Just-Enough-Access (JEA) for admin rights.
· Start enforcing risk-based authentication.
Metrics: 98% MFA coverage; <1% persistent global admin accounts.
Stage 2: Secure and Validate Devices
Objective: Access depends on the “health” of endpoints.
Actions:
· Enroll devices into management (MDM/EDR).
· Enforce compliance (encryption, patches, threat agents).
· Deny access from unmanaged or non-compliant devices.
Metrics: 95% managed devices; 98% EDR coverage.
Stage 3: Network Segmentation and ZTNA
Objective: Limit lateral movement through microsegmentation.
Actions:
· Deploy Zero Trust Network Access (ZTNA) or SDP gateways as PEPs.
· Create microsegments around key applications.
· Restrict East-West traffic between workloads.
Metrics: 70% reduction in accessible lateral movement paths; ≥95% of critical flows controlled by PEPs.
Stage 4: Data & Application-Level Controls
Objective: Implement access and protection at the data layer.
Actions:
· Classify and label data; apply Data Loss Prevention (DLP) policies.
· Secure machine-to-machine (M2M) connections with service identities.
· Apply Attribute-Based Access Control (ABAC).
Metrics: 90% of critical data labeled and policy-bound; 95% of services using verified identities.
Stage 5: Continuous Monitoring & Automation
Objective: Detect and respond dynamically — operate under “Assume Breach.”
Actions:
· Aggregate telemetry from IdP, PEP, and EDR into SIEM/XDR.
· Implement behavioral analytics and automated incident response (isolation, MFA re-auth).
· Measure MTTD (Mean Time to Detect) and MTTR (Mean Time to Respond).
Metrics: Detection time in minutes; 60% of incidents auto-contained.
The Future of Zero Trust and Trends
Zero Trust becomes a program, not a project — and gets measurable
Governments and large enterprises are moving from “adoption” to measuring maturity across identity, devices, network, apps/workloads, and data. CISA’s Zero Trust Maturity Model v2.0 is now the reference for staged progress (Traditional → Initial → Advanced → Optimal).
Passwordless becomes default, not niche
FIDO passkeys are crossing the chasm: billions of accounts and rapidly rising adoption across consumer and enterprise services. Microsoft, Google, and Apple are hard-pivoting to passwordless, with Microsoft even sunsetting password storage in Authenticator in 2025.
Post-quantum cryptography (PQC) enters real planning cycles
NIST finalized the first PQC standards (FIPS 203/204/205: Kyber, Dilithium, SPHINCS+) and plans FALCON next — making PQC migration a concrete, staged exercise rather than a hypothetical.
Convergence with SSE/SASE; ZTNA replaces VPN
Zero Trust Network Access is now the on-ramp for SSE/SASE programs; reports show ZTNA at the center of SSE adoption and continued erosion of legacy VPN.
Adaptive policies powered by richer signals (and more automation)
Modern BeyondCorp-style stacks push continuous, risk-based decisions that blend identity, device posture, and behavior. The industry emphasis is on unified Zero Trust systems and automated responses (re-auth, isolate, revoke).
Machine identity and workload-to-workload trust go mainstream
As microservices and APIs proliferate, Zero Trust extends to service identities and workload attestation (mTLS everywhere, short-lived certs, identity-aware sidecars/service mesh).
Zero Trust for OT/IoT/Edge & 5G
The perimeter dissolves further at factories, hospitals, and branches. Expect identity and posture for non-traditional endpoints and “least-privilege connectivity” to edge apps.
Other Services
Insomnia Security Scanner
AI-powered web application security scanner by CQR. Automated vulnerability discovery, exploit verification, and detailed reporting for modern applications.
Learn more
Infrastructure Protection by CRYEYE
Security audits via CryEye provide enterprise information security, protecting the entire infrastructure.
Learn more Penetration Testing
Find vulnerabilities across your entire business infrastructure before hackers do! At penetration testing consulting, we will select pentest methods and other custom cybersecurity recommendations for your business.
Learn more Social Engineering
Simulate real-world phishing, vishing, and pretexting attacks to measure and improve your team's security awareness and response capabilities.
Learn more Performance Testing
All kinds of load and performance testing of your system from the CQR online security company.
Learn more AI-Powered Vulnerability Assessment
Leverage artificial intelligence to discover, prioritize, and remediate vulnerabilities across your digital assets faster and more accurately than traditional scanners.
Learn more Cloud Security Audit (AWS / GCP / Azure)
Comprehensive security review of your cloud environments — IAM policies, network controls, data exposure, and misconfigurations across all major cloud platforms.
Learn more DevSecOps Integration
Embed security into every stage of your CI/CD pipeline. Automated SAST, DAST, SCA, and secret scanning so vulnerabilities are caught before they reach production.
Learn more API Security Testing
In-depth testing of REST, GraphQL, and SOAP APIs for authentication flaws, authorization bypasses, injection vulnerabilities, and data leakage risks.
Learn more Mobile Application Penetration Testing
Manual and automated security testing for iOS and Android applications — reverse engineering, runtime analysis, traffic interception, and backend API assessment.
Learn more IoT Security Assessment
Evaluate firmware, communication protocols, cloud backends, and physical interfaces of IoT devices to identify vulnerabilities before attackers do.
Learn more Blockchain & Smart Contract Audit
Formal verification and manual code review of smart contracts on Ethereum, Solana, and other chains. Detect reentrancy, overflow, and logic flaws before deployment.
Learn more Red Team Operations
Advanced adversary simulation using real attacker TTPs (MITRE ATT&CK) to test your detection, response, and overall security posture under realistic conditions.
Learn more Threat Intelligence & Monitoring
Continuous monitoring of threat feeds, dark web, and attacker infrastructure to provide actionable intelligence specific to your organization and industry.
Learn more Zero Trust Architecture Review
Assess and design your Zero Trust security model — identity verification, micro-segmentation, least-privilege access, and continuous validation controls.
Learn more Compliance Consulting (PCI DSS / SOC 2 / GDPR)
Expert guidance to achieve and maintain compliance with major security frameworks. Gap analysis, remediation roadmaps, and audit-readiness support.
Learn more Dark Web Monitoring
Continuous surveillance of dark web forums, marketplaces, and breach databases for leaked credentials, sensitive data, or mentions of your organization.
Learn more Phishing Simulation & Awareness Training
Controlled phishing campaigns combined with interactive security awareness training to build a human firewall across your entire organization.
Learn more Supply Chain Security Audit
Assess third-party vendor risks, open-source dependencies, and software supply chain integrity to prevent attacks like SolarWinds and Log4Shell.
Learn more Container & Kubernetes Security
Security review of Docker images, Kubernetes clusters, RBAC policies, network policies, and runtime configurations to harden your container infrastructure.
Learn more Web Application Firewall (WAF) Deployment
Professional WAF setup, rule tuning, and ongoing management to block SQL injection, XSS, CSRF, and other OWASP Top 10 threats in real time.
Learn more Bug Bounty Program Management
Full lifecycle management of your bug bounty program — scope definition, researcher coordination, triage, validation, and remediation tracking.
Learn more OSINT Investigation Services
Open-source intelligence gathering on individuals, organizations, and infrastructure. Ideal for pre-engagement recon, fraud investigation, and competitive analysis.
Learn more Digital Forensics & Incident Response
Rapid response to security breaches — evidence collection, malware analysis, attacker timeline reconstruction, and actionable remediation recommendations.
Learn more