What Is Shadow Data? Examples, Risks and How to Detect It

Modern cloud environments contain vast amounts of data stored in object storage services such as Amazon S3, Google Cloud Storage, and Azure Blob Storage. In large organizations, a single data store can contain billions (or even tens of billions) of objects. In this reality, traditional approaches that rely on scanning every file to detect sensitive data quickly become impractical.

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Full object-level inspection is expensive, slow, and difficult to sustain over time. It increases cloud costs, extends onboarding timelines, and often fails to keep pace with continuously changing data. As a result, modern data security platforms must adopt more intelligent techniques to build accurate data inventories and sensitivity models without scanning every object.

Why Object-Level Scanning Fails at Scale

Object storage systems expose data as individual objects, but treating each object as an independent unit of analysis does not reflect how data is actually created, stored, or used.

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In large environments, scanning every object introduces several challenges:

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• Cost amplification from repeated content inspection at massive scale
  
• Long time to actionable insights during the first scan
  
• Operational bottlenecks that prevent continuous scanning
  
• Diminishing returns, as many objects contain redundant or structurally identical data
  
  

The goal of data discovery is not exhaustive inspection, but rather accurate understanding of where sensitive data exists and how it is organized.

The Dataset as the Correct Unit of Analysis

Although cloud storage presents data as individual objects, most data is logically organized into datasets. These datasets often follow consistent structural patterns such as:

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• Time-based partitions
  
• Application or service-specific logs
  
• Data lake tables and exports
  
• Periodic reports or snapshots
  
  

For example, the following objects are separate files but collectively represent a single dataset:

logs/2026/01/01/app_events_001.json

logs/2026/01/02/app_events_002.json

logs/2026/01/03/app_events_003.json

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While these objects differ by date, their structure, schema, and sensitivity characteristics are typically consistent. Treating them as a single dataset enables more accurate and scalable analysis.

Analyzing Storage Structure Without Reading Every File

Modern data discovery platforms begin by analyzing storage metadata and object structure, rather than file contents.

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This includes examining:

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• Object paths and prefixes
  
• Naming conventions and partition keys
  
• Repeating directory patterns
  
• Object counts and distribution
  
  

By identifying recurring patterns and natural boundaries in storage layouts, platforms can infer how objects relate to one another and where dataset boundaries exist. This analysis does not require reading object contents and can be performed efficiently at cloud scale.

Configurable by Design

Sampling can be disabled for specific data sources, and the dataset grouping algorithm can be adjusted by the user. This allows teams to tailor the discovery process to their environment and needs.

Automatic Grouping into Dataset-Level Assets

Using structural analysis, objects are automatically grouped into dataset-level assets. Clustering algorithms identify related objects based on path similarity, partitioning schemes, and organizational patterns. This process requires no manual configuration and adapts as new objects are added. Once grouped, these datasets become the primary unit for further analysis, replacing object-by-object inspection with a more meaningful abstraction.

Representative Sampling for Sensitivity Inference

After grouping, sensitivity analysis is performed using representative sampling. Instead of inspecting every object, the platform selects a small, statistically meaningful subset of files from each dataset.

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Sampling strategies account for factors such as:

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• Partition structure
  
• File size and format
  
• Schema variation within the dataset
  
  

By analyzing these samples, the platform can accurately infer the presence of sensitive data across the entire dataset. This approach preserves accuracy while dramatically reducing the amount of data that must be scanned.

Handling Non-Standard Storage Layouts

In some environments, storage layouts may follow unconventional or highly customized naming schemes that automated grouping cannot fully interpret. In these cases, manual grouping provides additional precision. Security analysts can define logical dataset boundaries, often supported by LLM-assisted analysis to better understand complex or ambiguous structures. Once defined, the same sampling and inference mechanisms are applied, ensuring consistent sensitivity assessment even in edge cases.

Scalability, Cost, and Operational Impact

By combining structural analysis, grouping, and representative sampling, this approach enables:

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• Scalable data discovery across millions or billions of objects
  
• Predictable and significantly reduced cloud scanning costs
  
• Faster onboarding and continuous visibility as data changes
  
• High confidence sensitivity models without exhaustive inspection
  
  

This model aligns with the realities of modern cloud environments, where data volume and velocity continue to increase.

From Discovery to Classification and Continuous Risk Management

Dataset-level asset discovery forms the foundation for scalable classification, access governance, and risk detection. Once assets are defined at the dataset level, classification becomes more accurate and easier to maintain over time. This enables downstream use cases such as identifying over-permissioned access, detecting risky data exposure, and managing AI-driven data access patterns.

Applying These Principles in Practice

Platforms like Sentra apply these principles to help organizations discover, classify, and govern sensitive data at cloud scale - without relying on full object-level scans. By focusing on dataset-level discovery and intelligent sampling, Sentra enables continuous visibility into sensitive data while keeping costs and operational overhead under control.

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Managing access to sensitive information is becoming one of the most critical challenges for organizations in 2026. As data sprawls across cloud platforms, SaaS applications, and on-premises systems, enterprises face compliance violations, security breaches, and operational inefficiencies. Data Access Governance Tools provide automated discovery, classification, and access control capabilities that ensure only authorized users interact with sensitive data. This article examines the leading platforms, essential features, and implementation strategies for effective data access governance.

Best Data Access Governance Tools

The market offers several categories of solutions, each addressing different aspects of data access governance. Enterprise platforms like Collibra, Informatica Cloud Data Governance, and Atlan deliver comprehensive metadata management, automated workflows, and detailed data lineage tracking across complex data estates.

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Specialized Data Access Governance (DAG) platforms focus on permissions and entitlements. Varonis, Immuta, and Securiti provide continuous permission mapping, risk analytics, and automated access reviews. Varonis identifies toxic combinations by discovering and classifying sensitive data, then correlating classifications with access controls to flag scenarios where high-sensitivity files have overly broad permissions.

User Reviews and Feedback

Varonis

• Detailed file access analysis and real-time protection capabilities
• Excellent at identifying toxic permission combinations
• Learning curve during initial implementation

BigID

• AI-powered classification with over 95% accuracy
• Handles both structured and unstructured data effectively
• Strong privacy automation features
• Technical support response times could be improved

OneTrust

• User-friendly interface and comprehensive privacy management
• Deep integration into compliance frameworks
• Robust feature set requires organizational support to fully leverage

Sentra

• Effective data discovery and automation capabilities (January 2026 reviews)
• Significantly enhances security posture and streamlines audit processes
• Reduces cloud storage costs by approximately 20%

Critical Capabilities for Modern Data Access Governance

Effective platforms must deliver several core capabilities to address today's challenges:

Unified Visibility

Tools need comprehensive visibility across IaaS, PaaS, SaaS, and on-premises environments without moving data from its original location. This "in-environment" architecture ensures data never leaves organizational control while enabling complete governance.

Dynamic Data Movement Tracking

Advanced platforms monitor when sensitive assets flow between regions, migrate from production to development, or enter AI pipelines. This goes beyond static location mapping to provide real-time visibility into data transformations and transfers.

Automated Classification

Modern tools leverage AI and machine learning to identify sensitive data with high accuracy, then apply appropriate tags that drive downstream policy enforcement. Deep integration with native cloud security tools, particularly Microsoft Purview, enables seamless policy enforcement.

Toxic Combination Detection

Platforms must correlate data sensitivity with access permissions to identify scenarios where highly sensitive information has broad or misconfigured controls. Once detected, systems should provide remediation guidance or trigger automated actions.

Infrastructure and Integration Considerations

Deployment architecture significantly impacts governance effectiveness. Agentless solutions connecting via cloud provider APIs offer zero impact on production latency and simplified deployment. Some platforms use hybrid approaches combining agentless scanning with lightweight collectors when additional visibility is required.

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Open Source Data Governance Tools

Organizations seeking cost-effective or customizable solutions can leverage open source tools. Apache Atlas, originally designed for Hadoop environments, provides mature governance capabilities that, when integrated with Apache Ranger, support tag-based policy management for flexible access control.

DataHub, developed at LinkedIn, features AI-powered metadata ingestion and role-based access control. OpenMetadata offers a unified metadata platform consolidating information across data sources with data lineage tracking and customized workflows.

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While open source tools provide foundational capabilities, metadata cataloging, data lineage tracking, and basic access controls, achieving enterprise-grade governance typically requires additional customization, integration work, and infrastructure investment. The software is free, but self-hosting means accounting for operational costs and expertise needed to maintain these platforms.

Understanding the Gartner Magic Quadrant for Data Governance Tools

Gartner's Magic Quadrant assesses vendors on ability to execute and completeness of vision. For data access governance, Gartner examines how effectively platforms define, automate, and enforce policies controlling user access to data.

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Many security stacks look impressive at first glance. There is a DLP agent on every endpoint, a CASB or SSE proxy watching SaaS traffic, EDR and SIEM for hosts and logs, and perhaps a handful of identity and access governance tools. Yet when a serious incident is investigated, it often turns out that sensitive data moved through a path nobody was really watching, or that multiple tools saw fragments of the story but never connected them.

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The common thread is that most stacks were built around infrastructure, not data. They understand networks, workloads, and log lines, but they don’t share a single, consistent understanding of:

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• What your sensitive data is
• Where it actually lives
• Who and what can access it
• How it moves across cloud, SaaS, and AI systems

To move beyond that, security leaders are converging on a data‑first architecture that brings together four capabilities: DSPM (Data Security Posture Management), DLP (Data Loss Prevention), DAG (Data Access Governance), and DDR (Data Detection & Response) in a unified model.

Clarifying the Roles

At the heart of this architecture is DSPM. DSPM is your data‑at‑rest intelligence layer. It continuously discovers data across clouds, SaaS, on‑prem, and AI pipelines, classifies it, and maps its posture; configurations, locations, access paths, and regulatory obligations. Instead of a static inventory, you get a living view of where sensitive data resides and how risky it is.

DLP sits at the edges of the system. Its job is to enforce policy on data in motion and in use: emails leaving the organization, files uploaded to the web, documents synced to endpoints, content copied into SaaS apps, or responses generated by AI tools. DLP decides whether to block, encrypt, quarantine, or simply log based on policies and the context it receives.

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DAG bridges the gap between “what” and “who.” It’s responsible for least‑privilege access; understanding which human and machine identities can access which datasets, whether they really need that access, and what toxic combinations exist when sensitive data is exposed to broad groups or powerful service accounts.

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DDR closes the loop. It monitors access to and movement of sensitive data in real time, looking for unusual or risky behavior: anomalous downloads, mass exports, unusual cross‑region copies, suspicious AI usage. When something looks wrong, DDR triggers detections, enriches them with data context, and kicks off remediation workflows.

When these four functions work together, you get a stack that doesn’t just warn you about potential issues; it actively reduces your exposure and stops exfiltration in motion.

Why “DSPM vs DLP” Is the Wrong Framing

It’s tempting to think of DSPM and DLP as competing answers to the same problem. In reality, they address different parts of the lifecycle. DSPM shows you what’s at risk and where; DLP controls how that risk can materialize as data moves.

Trying to use DLP as a discovery and classification engine is what leads to the noise and blind spots described in the previous section. Conversely, running DSPM without any enforcement at the edges leaves you with excellent visibility but too little control over where data can go.

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DSPM and DAG reduce your attack surface; DLP and DDR reduce your blast radius. DSPM and DAG shrink the pool of exposed data and over‑privileged identities. DLP and DDR watch the edges and intervene when data starts to move in risky ways.

A Unified, Data‑First Reference Architecture

In a data‑first architecture, DSPM sits at the center, connected API‑first into cloud accounts, SaaS platforms, data warehouses, on‑prem file systems, and AI infrastructure. It continuously updates an inventory of data assets, understands which are sensitive or regulated, and applies labels and context that other tools can use.

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On top of that, DAG analyzes which users, groups, service principals, and AI agents can access each dataset. Over‑privileged access is identified and remediated, sometimes automatically: by tightening IAM roles, restricting sharing, or revoking legacy permissions. The result is a significant reduction in the number of places where a single identity can cause significant damage.

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DLP then reads the labels and access context from DSPM and DAG instead of inferring everything from scratch. Email and endpoint DLP, cloud DLP via SSE/CASB, and even platform‑native solutions like Purview DLP all begin enforcing on the same sensitivity definitions and labels. Policies become more straightforward: “Block Highly Confidential outside the tenant,” “Encrypt PHI sent to external partners,” “Require justification for Customer‑Identifiable data leaving a certain region.”

DDR runs alongside this, monitoring how labeled data actually moves. It can see when a typically quiet user suddenly downloads thousands of PHI records, when a service account starts copying IP into a new data store, or when an AI tool begins interacting with a dataset marked off‑limits. Because DDR is fed by DSPM’s inventory and DAG’s access graph, detections are both higher fidelity and easier to interpret.

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From there, integration points into SIEM, SOAR, IAM/CIEM, ITSM, and AI gateways allow you to orchestrate end‑to‑end responses: open tickets, notify owners, roll back risky changes, block certain actions, or update policies.

Where Sentra Fits

Sentra’s product vision aligns directly with this data‑first model. Rather than treating DSPM, DAG, DDR, and DLP intelligence as separate products, Sentra brings them together into a single, cloud‑native data security platform.

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That means you get:

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• DSPM that discovers and classifies data across cloud, SaaS, on‑prem, and AI
• DAG that maps and rationalizes access to that data
• DDR that monitors sensitive data in motion and detects threats
• Integrations that feed this intelligence into DLP, SSE/CASB, Purview, EDR, and other controls

In other words, Sentra is positioned as the brain of the data‑first stack, giving DLP and the rest of your security stack the insight they need to actually stop exfiltration, not just report on it afterward.

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