TL;DR: Hospital image archives remain reachable from the public internet despite decades of DICOM security options, according to Crayonic, with researchers finding 3,627 DICOM servers in more than 100 countries and 99.56% accepting connections without checking the caller's AE title. The control gap is governance, not technology: imaging systems are still treated like back-office appliances instead of front doors.
At a glance
What this is: NHI Mgmt Group's analysis, drawing on Crayonic's blog post: Hospital DICOM archives remain broadly exposed online because encryption and caller identity checks are optional in practice, not enforced by default.
Why it matters: This matters because clinical image platforms often sit outside normal identity and asset governance, so exposed viewers and archives can bypass the access controls that protect the rest of the hospital environment.
By the numbers:
- Researchers found 3,627 DICOM servers in more than 100 countries answering anyone who asked.
- Only 0.14% were seen using TLS.
- 99.56% accepted connections without checking the caller's application entity title.
Context
DICOM is the protocol that lets scanners, archives, viewers and clinical workstations exchange medical images. The security problem is not that the standard lacks controls, but that deployments commonly treat those controls as optional and leave them unactivated.
That gap matters because imaging environments often grow through separate projects, vendor links and remote viewing arrangements, which leaves identity and perimeter ownership fragmented. In practice, the archive can end up exposed even when the rest of the hospital has stronger access governance.
Key questions
Q: What should teams do first when a PACS or DICOM server is exposed?
A: First isolate the reachable imaging endpoint, remove any direct internet exposure, and confirm whether the PACS or DICOM server is intended to accept external associations at all. Then restrict access with network segmentation, firewall allow-lists, authenticated remote access, and logging on DICOM association attempts, because an exposed server can still be probed even if images are not yet accessible.
Q: Why is AE title not enough for DICOM access control?
A: AE Title is only a DICOM application identifier, not an access control mechanism. It can help route associations to the right device or application, but it does not authenticate the caller, prove network location, or enforce user, certificate, or role-based authorisation, so it must be paired with network controls and authenticated transport.
Q: How should hospitals secure remote access to medical image archives?
A: Hospitals should secure remote access to medical image archives with strong user authentication, MFA, encrypted connections, least privilege, and time-limited role-based access to the archive application and file shares. Remote sessions should be logged, monitored, and revoked quickly. Privileged admin access should go through PAM, separate from routine clinical access.
Q: What is the best way to govern vendor access to PACS systems?
A: The best way to govern vendor access to PACS systems is to give each vendor a unique, named account with least privilege, MFA, and JIT elevation only for approved support tasks. Access should be time bound, session recorded, tied to a ticket, and removed when the contract or maintenance need ends. Shared accounts should be avoided.
Technical breakdown
Why AE title checking is not real authentication
DICOM systems often use the application entity title, or AE title, as a way to identify a connecting system. The weakness is that AE title is a caller-supplied label, not a cryptographic proof of identity. If a server accepts that label as the main gate, any client that knows the interface can present a plausible name and still reach the archive. That creates the appearance of access control without the assurance of authentication. The result is especially fragile in environments where modalities, viewers and vendor tools all connect across trust boundaries.
Practical implication: Treat AE title only as an identifier for routing or inventory, not as a substitute for authenticated access.
How optional TLS and mutual authentication leave imaging traffic exposed
DICOM supports encryption, but support is not the same as enforcement. Servers may claim a TLS profile, may disable mutual authentication, or may never enable the profile at all. That means image traffic can remain readable in transit or exposed to unauthorized connections even when the protocol itself has the right features. In operational terms, the security posture depends on local configuration choices, procurement requirements and whether the archive is placed behind network controls. Optional security settings are a common failure mode in hospital imaging because they survive for years without an owner testing them.
Practical implication: Require encrypted transport and certificate-backed authentication for every imaging system that crosses a trust boundary.
Why PACS exposure is an identity and governance problem
A PACS archive is not just storage. It is a sensitive data service with user access, vendor access and often remote viewing paths that should be governed like any other privileged application. When those paths are unmanaged, the archive becomes a de facto public front door. The article's pattern is familiar across identity security: the system has a real access model, but the model is not wired into the organisation's broader identity lifecycle, asset inventory or offboarding discipline. That leaves exposure to persist long after the original project owner moves on.
Practical implication: Fold PACS, viewers and remote vendor access into the same inventory, review and offboarding processes as other privileged systems.
Threat narrative
Attacker objective: The attacker or unauthorised user seeks access to medical images and associated patient data without going through proper clinical access controls.
- Entry occurs when an exposed DICOM listener or web viewer accepts outside connections from the public internet.
- Credential access is avoided or weakened because the archive relies on optional transport protection and caller-supplied AE titles instead of strong authentication.
- Escalation happens when an unauthorised user can enumerate, view or retrieve medical images through the exposed archive or its front-end portal.
- Impact is exposure of patient imaging data, delayed detection and regulatory action long after the system was first left reachable.
Breaches seen in the wild
- Firebase misconfiguration exposure 2024: Missing Firebase security rules on 916 websites exposed 125 million user records and 19.87 million plaintext passwords; a quarter were fixed.
- Salesloft OAuth token breach: hackers stole OAuth tokens to access Salesforce data via Salesloft.
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
Imaging exposure is an identity governance failure, not just a network hygiene issue. DICOM environments often have a real access model, but it is fragmented across scanners, archives, viewers and vendor connections. When identity is reduced to a text label or a local configuration choice, the organisation loses the ability to govern who can reach the archive at all. The right lens is lifecycle control over every system that can read or serve images.
AE title trust creates a false sense of access control. A caller-supplied label is useful for routing, but it is not a trustworthy identity proof and should never be treated as one. That distinction matters because many clinical systems inherit a pattern where naming and authorisation are conflated. Practitioners should treat this as a named failure mode, not a tuning issue.
Hospital imaging now behaves like a distributed service surface. Modalities, teleradiology links, web viewers and remote vendor access all extend the blast radius of a single exposed archive. The governance question is therefore who owns the perimeter end to end, not whether the PACS team enabled a feature. If no one owns the full service path, exposure is predictable.
DICOM security only works when policy is enforced outside the protocol. The standard offers encryption, logging and authenticated transport options, but the deployment model determines whether those options matter. That makes procurement language, asset inventory and access review the real control plane. If the hospital cannot prove those controls, the archive is already overexposed.
Front-door imaging: hospital archives need to be governed like internet-facing services, because the operational reality is that they often are. That means the security model must assume discovery, probing and unauthorised connection attempts will happen. The practical conclusion is to bring imaging under the same identity and exposure governance used for other sensitive services.
From our research library:
- 92% of organisations expose NHIs to third parties, raising concerns about supply chain security, according to the Ultimate Guide to NHIs.
- Read next: How to find hard-coded secrets in container images
What this signals
Imaging exposure management: hospital environments need a specific programme for internet-reachable clinical systems, because standard asset inventories often miss viewers, vendor portals and hidden listeners. The next control step is to move these services into the same exposure management rhythm used for other sensitive external assets.
The practical shift for security teams is to stop treating PACS as an isolated clinical appliance and start treating it as a governed service surface. That means aligning authentication, network placement and offboarding with the rest of the identity programme, especially where remote access and third-party support are involved.
If a hospital cannot answer who can connect to an image archive, how that access is authenticated and whether it is visible in logs, the governance model is incomplete. The control objective is not perfect protocol purity, but provable reachability limits and accountable access paths.
For practitioners
- Inventory every exposed imaging endpoint Scan internal and external address space for DICOM listeners and the web viewers attached to them, then reconcile what you find against the asset register and vendor-run instances.
- Remove public internet exposure from PACS Place image archives behind a firewall or VPN where possible, and require a deliberate access path instead of direct public reachability.
- Replace label-based trust with real authentication Use certificate-based authentication and strong identity provider controls for viewers, teleradiology portals and vendor engineers, not AE title checks alone.
- Require mutual TLS for supported imaging systems Turn on the DICOM TLS profile where modalities and archives support it, and verify that mutual authentication is actually enforced in production.
- Write imaging access into procurement and operations Make encryption, access logging, patching and offboarding requirements part of the next imaging purchase and the current operating model.
Key takeaways
- Exposed imaging archives persist because optional protocol security, weak caller identity and generous defaults create a durable access gap.
- Researchers found 3,627 DICOM servers in more than 100 countries, and 99.56% accepted connections without checking AE title.
- Hospitals should govern PACS, viewers and vendor access as front-door services, with strong authentication, encrypted transport and full asset inventory.
Related NHI Mgmt Group resources: How to find hard-coded secrets in container images · Privacy-Respecting Browsers and Search Guide · AI Agent Tool and Plugin Security Guide
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 addresses the attack surface, NIST CSF 2.0, NIST SP 800-53 Rev 5 and CIS Controls v8 set the technical controls, and ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AA-05 — Access Permissions, Entitlements and Authorizations | DICOM exposure here is fundamentally an access-control failure across image archives and viewers. |
| Recommendation — Apply PR.AA-05 to enforce authenticated, least-privilege access for every imaging service and portal. | ||
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | The article highlights weak credential and authentication handling across imaging endpoints and portals. |
| Recommendation — Use IA-5 to manage authenticators for PACS, viewers and vendor access instead of relying on labels. | ||
| ISO/IEC 27001:2022 | A.5.15 — Access control | Imaging systems need explicit access control rules because default exposure leaves them reachable from outside. |
| Recommendation — Define and enforce access control rules for imaging services, including remote and third-party connections. | ||
| CIS Controls v8 | CIS-5 — Account Management | Shared portals and vendor access make account lifecycle control central to PACS governance. |
| Recommendation — Track, review and remove imaging accounts and vendor access paths under CIS-5. | ||
| OWASP Non-Human Identity Top 10 | NHI-04 — Insecure Authentication | When imaging services trust caller labels or weak defaults, they exhibit insecure authentication patterns. |
| Recommendation — Replace label-based trust with strong authentication for every non-human access path. | ||
Key terms
- DICOM Association: A DICOM association is the negotiated network session between two DICOM application entities. It establishes how they will exchange medical imaging messages, including calling and called roles, presentation contexts, and transfer syntax. The association must be accepted before DIMSE services such as storage or query can run.
- AE Title: AE Title is a DICOM application identifier used to name a device or software endpoint on the network. It helps a DICOM node decide where to send or accept associations, but it is not a secret and does not by itself authenticate a system or control authorisation.
- PACS: Physical Access Control Systems are the systems that decide whether a badge, mobile credential, or biometric token can open a door or enter a restricted area. They are access enforcement points, not lifecycle governance systems, so they can log entry events without understanding the broader employment or role context behind them.
- Mutual Authentication: Mutual authentication is a two-way verification process where each party proves its identity before communication proceeds. In connected operational systems, it prevents devices and services from trusting unauthenticated peers and helps enforce identity-first security across distributed environments.
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Published by the NHIMG editorial team on November 4, 2026.
NHI Mgmt Group, the independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org