By NHI Mgmt Group Editorial TeamBased on Sentra: “Specialized File Format Scanning: DICOM, Tableau, Pickle, and the “We Don’t Scan That” Problem” (March 22, 2026)

TL;DR: Specialized file formats such as DICOM, EDI, Tableau extracts, pickle files, OneNote notebooks, Draw.io diagrams, Java KeyStores, and LST catalogs often bypass traditional DLP and DSPM coverage because tools treat them as opaque blobs, according to Sentra. That gap leaves regulated data, secrets, and shadow copies hidden in the files teams use every day, so file-format parsing is becoming a governance requirement, not a niche feature.


At a glance

What this is: Specialized file formats can hide regulated data, secrets, and shadow copies because mainstream DSPM and DLP tools often cannot parse them properly.

Why it matters: IAM, data security, and NHI teams need visibility into these files because hidden metadata, embedded credentials, and unmanaged copies can bypass standard governance controls.


Context

Most data security programmes are built around files humans recognise at a glance, such as PDFs, Office documents, and spreadsheets. That assumption breaks down when sensitive information is embedded in container-like formats, where the value lies in metadata, labels, serialized objects, or extracted tables rather than the visible file name or extension.

In DSPM terms, the gap is not storage location alone but content understanding. Where specialised formats also carry secrets, certificates, or other non-human identity material, the visibility problem becomes an identity governance problem as well as a data classification problem.


Key questions

Q: What breaks when DSPM cannot parse specialised file formats?

A: The control sees only a file wrapper, not the regulated data, metadata, or keys embedded inside it. That means classification, retention, and access decisions are made on incomplete evidence, which creates blind spots in inventory and governance. In practice, unsupported formats become invisible storage for sensitive content rather than governed assets.

Q: Why do specialised file formats create hidden data risk in cloud environments?

A: Cloud storage makes copying easy, but format opacity makes inspection hard. When derived files such as extracts, notebooks, or serialized objects move into buckets and shares, the organisation often loses the context that would normally trigger controls. The risk is not only storage sprawl, but unmanaged copies that retain regulated content or secrets.

Q: How should teams govern Java KeyStores and other file-based credentials?

A: Treat them as both sensitive data containers and identity-enabling artefacts. They should be inventoried, linked to the workloads that consume them, and included in rotation, revocation, and offboarding processes. If you only classify the file and do not govern the trust it represents, you still have an exposure problem.

Q: What is the difference between scanning a file and understanding its contents?

A: Scanning a file often means applying broad detection rules to the outer object, while understanding its contents means parsing the internal structure so sensitive fields, labels, or embedded secrets can be classified accurately. In specialised formats, that difference determines whether security sees the real data or only a misleading wrapper.


Technical breakdown

Why specialised file formats defeat content-based inspection

Traditional DLP and DSPM engines are strongest when they can apply pattern matching or document parsing to human-readable content. Specialised formats such as DICOM, EDI, pickle, joblib, and JKS bundle structured data inside wrappers that ordinary scanners may treat as opaque binary objects. That means the security control sees a file, not the identifiers, keys, or records inside it. The failure is architectural, not cosmetic: if the parser cannot normalise the content into fields, the classification engine never gets a trustworthy view of what is actually stored.

Practical implication: Treat parser coverage as a control requirement, not a feature request, and test whether your platform can extract content from each specialised format you store.

How hidden metadata becomes governed data and NHI risk

Several of these formats carry more than business data. DICOM can include patient identifiers in metadata, Tableau extracts can create shadow copies of regulated records, and Java KeyStores hold certificates and private keys that underpin workload authentication. That creates a direct bridge between data security and non-human identity governance because keys, tokens, and certificates are not just sensitive artefacts, they are access mechanisms. If the platform cannot see them, it cannot classify them, scope them, or correlate them with the systems and identities they protect.

Practical implication: Inventory specialised files alongside the credentials and certificates they contain or protect, so data governance and NHI governance are assessed together.

Why AI and analytics workflows amplify the exposure

Modern analytics and machine learning pipelines regularly generate specialised file types as byproducts of normal work. Analysts export local extracts, researchers move DICOM studies to cloud storage, and data scientists serialise objects into pickle or joblib files that may embed training samples or feature data. These artefacts are then shared, copied, and archived outside the original system of record. The governance problem is that the most sensitive copy is often the one created for convenience, not the canonical source. Without specialised parsing, DSPM sees a repository of files, not a network of derived data assets.

Practical implication: Extend classification and access review to derived analytics and ML artefacts, not just source databases and obvious document repositories.


Threat narrative

Attacker objective: The objective is to find high-value data or credential material that governance tools failed to inspect because it was stored inside an unsupported file format.

  1. Entry occurs when sensitive records, credentials, or keys are exported into specialised file formats during routine healthcare, analytics, or application workflows.
  2. Credential or data access is preserved inside the file itself because standard controls often cannot parse the embedded metadata, serialized objects, or certificate material.
  3. Exposure escalates when those files are copied into cloud buckets, shares, research environments, or collaboration tools where governance visibility is weaker.
  4. Impact is hidden retention of regulated data, secrets, and shadow copies that can be misused, leaked, or left undiscovered for long periods.
  • Oracle Cloud breach claim 2025: A hacker claims 6 million Oracle Cloud SSO records, keystores and keys; Oracle denies a cloud breach but admits two obsolete servers were hit.

Read and download The State of NHI & AI Agent Breach Report 2026, covering 200+ breaches impacting Non-Human Identities including AI Agents.


NHI Mgmt Group analysis

Specialised file format blind spots are a data governance failure, not a niche parsing issue. If a DSPM platform cannot interpret the structure inside DICOM, EDI, Tableau extracts, notebooks, diagrams, or keystores, it is not governing the asset, only locating it. That creates a false sense of inventory completeness because the file exists in view while its real contents remain invisible. Practitioners should treat format coverage as part of the control baseline, not a secondary enhancement.

Java KeyStores turn the visibility gap into an identity problem as well as a data problem. A keystore is not just another opaque file, it is a container for the certificates and private keys that workload authentication depends on. When those files are undiscovered or unclassified, the organisation loses sight of where machine trust is anchored and which systems rely on it. Practitioners should align DSPM coverage with NHI inventory and certificate governance.

Shadow data is often created by legitimate workflows, which makes detection harder than exfiltration-centric models assume. Tableau extracts, exported EDI files, and serialized ML artefacts are frequently produced by authorised users for valid business reasons, then copied into places that are outside the intended control plane. That means the governance gap is lifecycle-based: data becomes risky when it leaves its source context and enters a less visible one. Practitioners should manage derived files as first-class governed assets.

Specialised format parsing is becoming a practical prerequisite for AI-ready security programmes. As organisations push more data into analytics, research, and model-building workflows, the number of non-standard artefacts rises with it. This widens the gap between what the business thinks it has, and what security can actually classify. Practitioners should assume that unsupported formats will accumulate and design controls that find and normalise them before exposure spreads.

What this signals

Specialised format coverage should be treated as a visibility control, not a convenience feature. Once organisations rely on analytics, imaging, collaboration, and serialization workflows, unsupported file types become a predictable place for sensitive data to hide. The programme impact is straightforward: if the scanner cannot interpret the container, the governance model is incomplete.

Java KeyStores sharpen the identity boundary inside DSPM. A file that contains certificates or private keys is also a trust anchor for workloads, not just a stored object. That is why data security teams and identity teams need a shared view of where those containers live and who can reach them.

Specialised file formats create shadow data because legitimate users produce them as part of normal work. The practical response is to extend classification, review, and retention controls to derived artefacts before they spread into cloud storage and collaboration systems.


For practitioners

  • Expand parser coverage for specialised formats Validate that your DSPM and DLP stack can extract content from DICOM, EDI, Tableau extracts, pickle or joblib files, OneNote notebooks, Draw.io diagrams, Java KeyStores, and LST catalogs, not just PDFs and Office documents.
  • Classify derived files as governed assets Add exported extracts, research copies, notebooks, and serialized ML artefacts to the same classification and retention rules you apply to source systems and databases.
  • Inventory keys and certificates in file stores Map Java KeyStores and similar containers to the workloads and applications that depend on them, then track where those files live across buckets, shares, and collaboration systems.
  • Review cloud locations for shadow copies Search object stores and file shares for specialised formats that may hold regulated data or secrets, especially where analytics, research, or integration workflows create temporary copies.
  • Tie file classification to access review Use the content discovered inside specialised formats to challenge who can access the file and whether that access is still appropriate for the data, keys, or metadata it contains.

Key takeaways

  • Specialised file formats can conceal regulated data, keys, and shadow copies even when core data stores are well governed.
  • The main failure is not storage discovery but content understanding, because unsupported parsers cannot classify what they cannot read.
  • Practitioners should expand DSPM, data classification, and NHI governance to cover derived files, serialized artefacts, and keystore containers.

Standards & Framework Alignment

This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.

OWASP Non-Human Identity Top 10 and MITRE ATT&CK address the attack and risk surface, while NIST CSF 2.0 sets the governance and control requirements practitioners need to meet.

FrameworkControl / ReferenceRelevance
OWASP Non-Human Identity Top 10NHI-02 — Secret LeakageJKS and similar containers can hide secrets from ordinary inspection in file stores.
NHI-07 — Long-Lived SecretsKeystores often persist far longer than their owning applications expect.
Recommendation — Scan file repositories for hidden secrets and revoke any credentials discovered inside specialised containers. Track keystore age and retire long-lived credential containers before they outlive their trust boundary.
NIST CSF 2.0PR.DS-01 — Data-at-rest is protectedSpecialised file formats often store regulated data at rest outside normal content controls.
PR.AA-05 — Access Permissions, Entitlements and AuthorizationsShadow copies in analytics and collaboration stores need governed access decisions.
Recommendation — Extend data-at-rest protections to file types your scanners cannot yet interpret reliably. Review permissions on derived file stores so access matches the sensitivity of the embedded content.
MITRE ATT&CKTA0009;TA0010 — Collection; ExfiltrationUnsupported file formats can mask collection and exfiltration of sensitive data or keys.
Recommendation — Map unsupported file locations to collection and exfiltration hunting so hidden assets are not overlooked.

Key terms

  • Specialised File Format: A specialised file format is a container that stores data in a structure not easily readable by generic security tools. Examples include DICOM, EDI, Tableau extracts, and keystores. The security issue is not the file extension itself, but whether the platform can extract and classify the contents accurately.
  • Shadow Data: Shadow data is sensitive information that exists outside the places security teams expect to find it. It often appears in testing copies, ad hoc exports, SaaS tools, or AI workflows, which makes it hard to govern with inventory-based controls alone.
  • Java KeyStore: A Java KeyStore is a file-based container used to hold certificates, private keys, and related trust material for Java applications. In security programmes, it matters because it is both sensitive data and an authentication dependency, so its location, age, and ownership need explicit governance.
  • Derived Data: Derived data is information created from original content through analysis, transformation, or extraction. For image AI, that includes descriptions, labels, and OCR text, all of which may carry the same sensitivity as the source and therefore need equivalent handling.

Deepen your knowledge

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NHIMG Editorial Note
Published by the NHIMG editorial team on August 19, 2026.
Updated on October 12, 2026.
NHI Mgmt Group, the independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org