At-rest scanning examines stored data, such as repositories, files, archives, and SaaS content, for secrets already sitting in place. It is used to uncover historical exposure that may have escaped during development or collaboration. This method is essential for finding dormant risk that real time controls can miss.
Expanded Definition
At-rest scanning is the process of inspecting stored content for exposed secrets after data has already been written to a repository, file system, archive, backup set, ticketing system, or SaaS workspace. Unlike inline or pre-commit detection, it is retrospective: it looks for risk that has accumulated over time, including credentials, API keys, certificates, and tokens that may have been copied into places that were not intended to hold them. In practice, it is part of a broader secret discovery and exposure management discipline that supports governance and incident response. The NIST Cybersecurity Framework 2.0 frames this kind of work under detecting and managing cybersecurity risk, especially where assets are distributed across teams and platforms.
Definitions vary across vendors on whether at-rest scanning includes only structured storage, or also unstructured collaboration content, archive snapshots, and replicas. For NHI governance, the distinction matters because dormant secrets often become the hidden link between human access, machine access, and service account misuse. At-rest scanning is therefore less about finding a single bad file and more about continuously reducing secret sprawl across the estate. The most common misapplication is treating at-rest scanning as a one-time compliance sweep, which occurs when organisations scan only during audits and miss new exposures introduced by routine collaboration and backup processes.
Examples and Use Cases
Implementing at-rest scanning rigorously often introduces coverage and performance tradeoffs, requiring organisations to weigh broad discovery against storage overhead, access constraints, and false positives.
- Scanning source code repositories and mirrored archives to find API keys committed long ago, even after the original branch has been deleted.
- Inspecting shared drives and document libraries for embedded credentials that were pasted into design docs, runbooks, or incident notes.
- Reviewing SaaS content, such as workspace exports and file attachments, for secrets that were introduced through collaboration rather than development workflows.
- Checking backups and cold storage for dormant exposures that escaped earlier controls and now persist in retained copies.
- Using policy-driven scanning to identify secrets in legacy repositories before NIST Cybersecurity Framework 2.0-aligned remediation workflows begin.
In mature programmes, findings from at-rest scanning are routed into ticketing, rotation, revocation, and access review processes so that exposure is not just detected but removed or neutralised.
Why It Matters for Security Teams
At-rest scanning matters because secrets often survive long after the event that created them. A key can be removed from active code, but remain in a wiki page, exported spreadsheet, object store snapshot, or cloned repository. That creates a long tail of exposure that real-time controls cannot fully address. For security teams, the operational value is in shrinking the attacker’s opportunities to harvest credentials from forgotten locations and in proving that secret governance extends beyond the development pipeline.
This is especially important for environments with NHI sprawl, where machine identities, automation tokens, and service credentials can be copied into operational artefacts by design. At-rest scanning gives teams a way to locate those artefacts before they become persistent footholds. It also supports incident response after a secret has already been exposed, because retention systems and shared content often outlive the original compromise event. Organisational risk typically becomes visible only after a breach review or audit uncovers dormant credentials, at which point at-rest scanning becomes operationally unavoidable to contain the exposure.
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 address the attack surface, NIST CSF 2.0, NIST SP 800-53 Rev 5 and NIST SP 800-63 set the technical controls, and ISO/IEC 27001:2022 define the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | DE.CM | Continuous monitoring and detection align with discovering dormant secret exposures at rest. |
| NIST SP 800-53 Rev 5 | CM-8 | Configuration and asset inventory controls support locating stored data repositories that hold secrets. |
| ISO/IEC 27001:2022 | A.8.12 | Data leakage prevention guidance supports identifying sensitive data, including secrets, in stored content. |
| OWASP Non-Human Identity Top 10 | NHI guidance addresses secret exposure in stored artefacts that can grant machine identity access. | |
| NIST SP 800-63 | Digital identity guidance informs credential handling where stored secrets can undermine assurance. |
Maintain an accurate repository inventory so scanning covers every storage location that can retain secrets.
