Key Takeaways
Hybrid cloud environments create risk at connection points where inconsistent access controls, split monitoring, and legacy authentication gaps allow attackers to exploit identity and lateral movement pathways.
40% of breaches involve multi-environment data, costing over $5M and taking 283 days to detect, highlighting visibility and response gaps in hybrid setups.
Credential abuse, third-party compromise, and misconfigurations dominate entry points, but impact escalates due to weak segmentation and excessive privileges.
Zero trust enforces identity-based access, least privilege, and microsegmentation to limit blast radius and stop cross-environment lateral movement.
Effective implementation depends on full asset visibility, unified policy enforcement, and continuous monitoring across both cloud and on-premises systems.
Most security teams did not architect their hybrid cloud environment. It grew. A legacy ERP that finance refused to migrate off-premises, a Kubernetes cluster a product team spun up in GCP without telling IT, three SaaS applications that became mission-critical before anyone ran a security assessment on them, and a VPN that was supposed to be temporary in 2020 and is still running. Add those decisions up and most enterprises are operating workloads across two or three cloud providers, on-premises data centers that never fully shut down, and remote users connecting from wherever they happen to be working that day. Securing that mix is genuinely difficult, and the difficulty is structural.
The breach data reflects this. IBM’s Cost of a Data Breach Report1 2024, based on Ponemon Institute research covering 604 organizations in 16 countries, found that 40% of all data breaches involved data stored across multiple environments, and that category was the most expensive in the entire study, averaging over $5 million per incident and taking 283 days to identify and contain. Nearly ten months. That is the gap between a breach occurring and a security team knowing about it, in environments that look like most enterprise hybrid cloud setups today.
Zero trust security is the framework built specifically for this problem. Nothing on the network gets automatic trust based on where it originates. Every access request, whether it comes from inside the data center or from a remote endpoint three continents away, gets evaluated against verified identity, current device health, and access policy before anything gets approved.
40%
of all data breaches involved data stored across multiple environments
30%
of 2025 breaches involved third-party compromise, double the prior year
$5M+
average cost of a breach spanning multiple cloud and on-premises environments
Why Hybrid Cloud Infrastructure Creates Unique Security Risks
Hybrid cloud environments fail at the joins. The points where on-premises systems hand off data to cloud workloads, where cloud services authenticate against on-premises directories, where API calls cross trust boundaries that were defined by different teams at different times with assumptions that no longer hold. Each of those handoffs is an access decision point. In most hybrid environments, those decision points are controlled inconsistently. That inconsistency is where attacks start.
A few patterns show up across organizations regardless of their size or how mature their security program is:
Privilege creep across accounts.
Permissions accumulate. Someone gets elevated access for a project, the project ends, and nobody removes the access. Multiply that by three years and several hundred access grants across cloud and on-premises systems and the result is a large, largely invisible attack surface made of forgotten permissions. The 2024 Verizon DBIR2, covering 30,458 security incidents, found stolen or compromised credentials as the leading initial access vector at 16% of breaches. Over-privileged, stale accounts are a recurring contributor.
Security policies stop at environment boundaries.
Controls enforced on-premises do not automatically extend to cloud workloads. A team with strong network access controls on its data center infrastructure may have almost no equivalent controls on the cloud workloads running the same business logic. Security teams often cannot clearly see both sides at once, and that gap is what attackers look for when they are planning lateral movement.
Risk: The Visibility Problem
CISOs Must Address
Understand your Hidden Visibility Gaps
Practical Playbook for Improving Visibility
How Fidelis helps
Legacy systems carry authentication gaps.
Older enterprise applications were designed for closed networks where everyone inside was assumed to be trustworthy. Many cannot natively support multi-factor authentication. Many do not integrate with modern identity providers. Connecting them to hybrid cloud infrastructure without additional controls wrapped around them turns those authentication weaknesses into documented, findable attack surface.
Split monitoring creates blind spots at the intersection.
Security teams running separate tools for cloud visibility and on-premises visibility have a gap wherever those environments overlap. An attacker moving laterally from a compromised cloud workload into an on-premises segment, or the reverse, travels through that gap. It is a known and well-documented problem. It is also one many organizations have not yet resolved.
None of this is exotic or unusual. These conditions describe the standard operating state of most enterprise hybrid environments. Attackers who specialize in hybrid cloud targets have built their playbooks around finding exactly these gaps, and they are reliably present.
Current Threat Intelligence: What the 2025 Data Shows
The Verizon 2025 Data Breach Investigations Report3, which analyzed 22,052 security incidents including 12,195 confirmed breaches, found third-party involvement in 30% of all breaches, double the prior year’s figure, with vulnerability exploitation as an initial access vector up 34%, and nearly half of all perimeter-device vulnerabilities still unresolved through the tracking period. That last figure is not a story about negligence. It reflects the arithmetic problem of closing vulnerabilities faster than new ones get introduced.
Credential abuse came in at 22% of initial access vectors. Vulnerability exploitation at 20%. Supply chain compromise at 30%. For hybrid cloud security teams, what matters is what happens after initial access. In environments where segmentation is weak and monitoring is split between cloud and on-premises tools, a stolen credential becomes access to a much larger blast radius than it would in a well-segmented environment. The initial compromise is often the straightforward part of the attack. The damage accumulates during the lateral movement phase that follows.
The table below maps the five threat vectors most relevant to hybrid cloud environments to their typical entry methods, downstream impact, and zero trust controls:
Threat VectorHow It Gets InImpact on Hybrid CloudZero Trust Counter
Stolen credentialsPhishing, credential stuffingLateral movement across cloud and on-premisesMFA at every access point, per-session verificationThird-party access abuseCompromised vendor or MSPTrusted connection used to reach downstream targetsLeast privilege scoping on all vendor accessCloud misconfigurationExposed APIs, open storage bucketsUnauthorized access to sensitive data storesContinuous posture management and auditingInsider privilege misuseLegitimate credentials, unauthorized scopeData exfiltration without triggering standard alertsBehavioral baselines, least privilege, JIT accessRansomware deliveryPhishing, RDP exploitationOperational shutdown across interconnected systemsMicrosegmentation, EDR and NDR coverage
One IBM 2024 finding that tends to get less coverage: 35% of breaches involved shadow data. That is data sitting in storage the security organization was not formally tracking or governing. Those incidents cost 16% more on average. In hybrid cloud environments, where data moves constantly between systems, In hybrid cloud environments, where data moves constantly between on-premises systems and cloud services, shadow data is not an edge case; it is a predictable byproduct of how organizations actually operate.
Zero Trust Principles Applied to Hybrid Cloud Security
“Never trust, always verify” is the phrase everyone knows. NIST Special Publication 800-2074, the authoritative federal guidance on zero trust architecture, defines it operationally: access decisions focus on protecting resources rather than network segments, because network location is no longer a reliable indicator of whether a connection is trustworthy. A server in a corporate data center is not inherently safer than one running in a cloud tenant. A device on the office Wi-Fi is not inherently more secure than one connecting over a home broadband connection. Location tells you very little. Identity, device health, and current access context tell you considerably more.
NIST SP 800-207A5, which extends the zero trust framework specifically to multi-cloud and hybrid environments, adds a requirement that most implementations overlook: service identities need the same authentication and authorization treatment as user identities. APIs, automated pipelines, and service accounts move data between on-premises systems and cloud services constantly and quietly, often with broad access permissions and minimal logging. In hybrid environments, that category of access is frequently the least monitored part of the attack surface, and it shows up in breach investigations accordingly.
The CISA Zero Trust Maturity Model Version 2.06 (April 2023) organizes implementation across five pillars. All five need coverage. Not just identity. Not just network. The table below maps each to its hybrid cloud application:
ZTMM PillarWhat It CoversHybrid Cloud ApplicationPrimary Control
IdentityVerify every user and non-person entity on every sessionUnified IAM spanning on-premises directories and cloud tenantsMFA, SSO, just-in-time provisioningDevicesValidate endpoint health before granting resource accessPosture checks applied equally to managed and unmanaged devicesEDR, device compliance policiesNetworksLimit lateral movement through segmentationIndependent microsegmentation of on-premises and cloud workloadsSoftware-defined perimeters, cloud security groupsApps and WorkloadsTreat every application as internet-accessibleConsistent controls on legacy apps and cloud-native services alikeZTNA, CNAPPDataClassify and protect data at rest and in transitData governance extended to cloud storage; shadow data eliminatedDLP, classification, encryption
The ZTMM gives no environment a default trust advantage. On-premises workloads and cloud workloads get the same verification scrutiny. Devices inside the office perimeter and remote endpoints are evaluated by the same posture criteria, and the sensitivity of the resource being requested factors into every access decision regardless of where the request originates. That consistency across environments is what makes zero trust architecture actually workable in hybrid infrastructure, where the physical or logical location of a user or resource has stopped being a useful security signal.
How to Implement Zero Trust Across a Hybrid Cloud Environment
Zero trust is not a product you purchase and deploy. Vendors will suggest otherwise, but the reality is that it is a series of architectural and policy decisions that need to be applied consistently across the full hybrid environment. Organizations that treat it as a procurement problem end up with point solutions covering parts of the environment. The ones that make progress treat it as an ongoing operational shift with defined phases and measurable milestones.
Step 1. Build an Accurate Inventory Before Touching Any Controls
Before any zero trust policy gets configured, security teams need an honest, current inventory of what actually exists: every user account, service account, device, application, API endpoint, data store, and network connection across both on-premises and cloud infrastructure. Not the inventory that exists in the configuration management database from eighteen months ago. The current one, including the assets that were never formally registered. Any asset outside the inventory is outside the scope of policy. That is not a theoretical concern; it is the mechanism by which most hybrid cloud breaches begin.
Automated asset discovery platforms reduce the time this takes and surface the connections that manual auditing misses: lateral API connections between cloud services and on-premises databases, shadow IT assets deployed without formal registration, outbound connections that carry real traffic but were never documented. The goal is a working map of every access path into the hybrid environment, complete enough to make access policy decisions against.
Step 2. Enforce Identity Verification and Least Privilege Across Every Access Point
Identity verification is the mechanism zero trust runs on. MFA needs to reach every access point without exception: cloud management consoles, administrative interfaces, legacy application portals, service-to-service authentication, and any replacement for legacy VPN access. Gaps in MFA coverage are where compromised credentials get used quietly for extended periods, sometimes months, before unusual behavior surfaces through other means.
The Zscaler ThreatLabz 2025 VPN Risk Report7 found that 56% of organizations experienced a VPN-related security breach in the prior year, and 65% plan to replace VPN with zero trust network access (ZTNA) within twelve months. The architectural reason is straightforward: VPN grants implicit access to a network segment, while ZTNA grants access to one specific resource for one specific session tied to a verified identity, which means that when credentials are stolen, the attacker reaches only what that account was explicitly authorized to access rather than a broad network segment with lateral movement potential.
For privileged access specifically, just-in-time provisioning replaces standing elevated permissions. Administrators get elevated access for a defined task and time window only, with a full audit trail; when the window closes, the access expires automatically. Permanent admin credentials are among the most valuable things an attacker can obtain in a hybrid cloud environment. JIT provisioning does not eliminate administrative access. It narrows the standing exposure to the hours the work actually requires.
Step 3. Microsegment to Contain Lateral Movement
IBM’s 2024 breach data documented a 61-day difference in breach lifecycle between organizations that detected internally versus those that found out through external disclosure. In a hybrid environment with weak or absent network segmentation, 61 days of undetected lateral movement across cloud workloads and on-premises systems is an enormous amount of time; attackers who specialize in this environment use that time specifically to reach backup systems, authentication infrastructure, and data stores that allow them to establish persistence and maximize eventual impact.
Microsegmentation applies per-workload access controls both on-premises and in cloud environments. Software-defined perimeters and host-based agents enforce policies that stop lateral movement at the zone boundary even when one zone is compromised. Legacy systems that cannot be microsegmented with modern tools need compensating controls built around them: strict access controls, behavioral monitoring, and no standing connections to sensitive data stores. Those compensating controls are a temporary measure. They need a migration timeline attached to them.
Step 4. Build Continuous Monitoring That Covers the Full Hybrid Environment
Internal detection saves close to $1 million per incident on average compared to external disclosure, and closes the breach lifecycle 61 days faster, according to IBM’s 2024 data. Both outcomes require monitoring coverage that spans the full environment. A security operation with strong cloud visibility and strong on-premises visibility but no correlation between the two will miss lateral movement that crosses the boundary between environments, because that movement looks normal in both siloed views and only becomes anomalous when correlated.
Fidelis Elevate®, our XDR platform, unifies hybrid cloud visibility through terrain-based cyber defense, automatically mapping attack paths across network, endpoint, cloud, and Active Directory layers in a single platform. Fidelis Network’s Deep Session Inspection® (DSI) provides real-time, full-content packet analysis across all ports/protocols—including encrypted TLS 1.3 traffic—for both on-premises and cloud workloads, surfacing lateral movement that crosses environment boundaries. Fidelis Halo® CNAPP adds cloud-native runtime protection, microsegmentation, and continuous compliance monitoring for AWS, Azure, and GCP workloads. Security teams get correlated, prioritized incidents rather than siloed dashboards.
Don’t let threats go unnoticed. See how Fidelis Elevate® helps you:
Identify and neutralize threats faster
Gain full visibility across your attack surface
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Step 5. Centralize Security Policy and Build a Consistent Review Cadence
Policy fragmentation reliably derails zero trust implementations in hybrid environments. AWS IAM, Azure Active Directory, and Google Cloud IAM are different systems. Different models, different naming conventions, different defaults. A policy that looks complete in one provider can have exploitable gaps in another, and attackers doing reconnaissance against hybrid cloud targets look for exactly those inconsistencies. Without a centralized enforcement layer sitting above the provider-native tools, there is no consistent baseline.
New cloud workloads and services need zero trust controls at deployment, not added retroactively when someone gets around to it. The window between deployment and policy coverage is an exposure window. Access policy reviews, data classification audits, and segmentation checks should run on a defined schedule and automatically after infrastructure changes. For organizations subject to federal requirements or in regulated industries, mapping progress against the CISA ZTMM8 pillars satisfies compliance requirements under Executive Order 140289 and provides a structured benchmark for communicating maturity over time.
Zero Trust Implementation Challenges in Hybrid Cloud Environments
Certain obstacles appear reliably during zero trust rollouts. They show up regardless of cloud maturity, team size, or budget. Planning for them in advance is more efficient than discovering them after an implementation has stalled and lost momentum.
Legacy application authentication gaps.
Older applications that cannot support MFA or integrate with modern identity providers are a real constraint, not just a planning gap. Excluding them from zero trust scope is a documented risk acceptance decision, not a security solution. The right approach is compensating controls, tighter behavioral monitoring, and network isolation around those systems while migration gets prioritized and resourced.
Policy inconsistencies across cloud providers.
AWS IAM, Azure Active Directory, and Google Cloud IAM are meaningfully different systems. Enforcing consistent zero trust controls across all three requires a centralized policy management layer above the provider-native tools. Without it, the policy that looks solid in one environment has gaps in another, and those gaps are findable.
Fidelis Halo® CNAPP provides this centralized policy layer, enforcing consistent Zero Trust controls across AWS IAM, Azure AD, and Google Cloud IAM from a single management plane. It discovers shadow IT, enforces least-privilege service accounts, and applies microsegmentation policies uniformly whether workloads run on-premises, in single-cloud, or across multi-cloud environments—eliminating the provider-specific gaps attackers target.
Alert volume that exceeds analyst capacity.
Adding security controls increases signal volume. Without cross-layer correlation and automated triage, security teams spend time classifying and closing alerts rather than investigating actual threats. XDR platforms designed for hybrid environments address this by correlating signals from network, endpoint, and cloud layers into contextualized, prioritized findings rather than raw alert feeds.
No clear metric for zero trust maturity.
Zero trust is not a binary condition; it is measured in coverage increments. The CISA ZTMM pillar structure gives security teams a concrete benchmark for tracking progress across all five pillars, reporting to leadership, and identifying where investment produces the most direct security impact.
Why the Timeline for Zero Trust Implementation Matters Now
Supply chain attacks accounted for 30% of breaches in the 2025 Verizon DBIR3, double the prior year. The attack model is reliable: compromise a software vendor, IT service provider, or managed security service, then use that trusted relationship to reach multiple downstream organizations simultaneously, often before anyone realizes a compromise has occurred. Hybrid cloud environments are particularly exposed because vendor and partner connections are common, and those connections often carry broader access permissions than a strict least-privilege model would grant.
The IBM 2025 Cost of a Data Breach Report10, covering incidents from March 2024 through February 2025, reported average US breach costs exceeding $10 million. Organizations using AI and automation extensively in prevention workflows incurred $2.2 million less per breach. The differentiator was detection and containment speed. Teams with better visibility across their full hybrid environment caught anomalies faster and stopped breaches before they propagated across both sides of the environment.
Cloud misconfiguration remains a high-frequency entry point. No sophisticated tradecraft required. An over-permissioned API key or exposed storage bucket is discoverable by automated scanning within hours of deployment, which means the exposure window is very short but also very reliably present. Continuous posture monitoring and automated configuration auditing, both components of a mature zero trust implementation, close that window before external parties find it rather than after.
According to Grand View Research, the global zero trust security market was valued at $36.96 billion in 2024 and is projected to reach $92.42 billion by 2030, a compound annual growth rate of 16.6%. North America holds the largest share. That budget trajectory reflects where enterprise security teams have concluded the risk actually sits, and where regulators have been pointing them for the past several years.
Putting Zero Trust Controls Into Practice
Hybrid cloud environments keep expanding because the business decisions that created them keep happening. Cloud migration is ongoing. Vendor integrations multiply. The range of device types and connection methods accessing enterprise resources is not contracting. Each of those factors adds to an attack surface that a perimeter-based security model cannot account for, because the relevant assets, users, and data are no longer inside any meaningful perimeter.
Zero trust removes the perimeter dependency from access decisions. Verification happens at the resource level, on the basis of verified identity and current device health. Least privilege access limits the scope of any single compromise to what that account was explicitly authorized to reach. Microsegmentation stops lateral movement at workload boundaries rather than letting it propagate unchecked through a flat network. Continuous monitoring that spans the full hybrid environment, cloud and on-premises together, surfaces anomalous behavior before it compounds. These controls are interdependent. Partial implementation produces partial protection.
Fidelis Security operationalizes Zero Trust across hybrid environments: Elevate® XDR delivers 9X faster post-breach detection through AI-driven terrain mapping and cross-layer correlation; Network DSI® eliminates hybrid blind spots with deep packet inspection of encrypted traffic across all protocols; Halo® CNAPP (formerly CloudPassage) automates cloud workload protection, microsegmentation, CSPM/CWPP, and compliance for containers and VMs across AWS/GCP/Azure/on-premises. These integrate natively to reduce MTTR from months to hours, proven across Fidelis customer deployments.
Organizations that moved early on zero trust controls are spending less on breach incidents and less on incident response. That gap is documented in the IBM data and has grown each year since 2020. Deferring zero trust investment is not a neutral decision. It is a bet that the current hybrid cloud security posture is adequate, placed against an attack surface that expands every quarter and a threat actor ecosystem that specifically targets the gaps that hybrid cloud setups create.
Citations
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