A public link is a shareable URL that lets someone outside the organisation access a file or resource without logging in through the normal internal access path. In SaaS environments, it becomes a governance issue when it outlives the business need or bypasses expected security controls.
Expanded Definition
A public link is a shareable URL that grants access to a file or resource without the recipient first authenticating through the organisation’s normal internal path. In practice, it can be a deliberate collaboration control or a weakly governed exposure point, depending on scope, expiry, and auditability.
In NHI and SaaS environments, the concern is not the link itself but the access model behind it. A public link may bypass RBAC, reduce the value of JIT approvals, and create access that is difficult to revoke once copied, forwarded, or indexed. Definitions vary across vendors because some treat password-protected or expiring links as “public” while others reserve the term for unauthenticated access with no additional gate. The operational question is whether the link is externally reachable, how long it remains valid, and whether its use is observable in line with NIST Cybersecurity Framework 2.0 and Zero Trust expectations.
The most common misapplication is treating a “share” setting as temporary when the link remains active after the business need ends and the file continues to be reachable from outside the trusted boundary.
Examples and Use Cases
Implementing public links rigorously often introduces collaboration friction, requiring organisations to weigh ease of sharing against the cost of persistent external exposure.
- A marketing team publishes a campaign asset through a link that expires after launch, with access logs reviewed as part of routine governance. That pattern is closer to controlled sharing than open distribution.
- A finance spreadsheet is exposed through a link that has no expiry and no download restriction, creating a standing access path that may outlive the approval that created it.
- A support engineer sends a customer a temporary document link, then disables it when the case closes. This is a practical example of time-bound access aligned with least privilege.
- An engineering group stores incident evidence behind a link that is later pasted into a ticketing system. The link remains retrievable long after the incident, which turns a narrow workflow into persistent exposure. The governance gap described in the Ultimate Guide to NHIs is relevant here because external sharing often intersects with service accounts, automation, and secrets handling.
- A file-sharing platform allows anonymous viewing, but the security team enforces watermarking, access review, and expiry. That combination reduces risk without fully removing the convenience of external distribution.
In many organisations, the policy decision is less about whether public links should exist and more about which data classes can ever be shared that way, under what approval model, and with what revocation guarantee.
Why It Matters in NHI Security
Public links become an NHI security issue when machine-to-machine workflows, service accounts, or automated agents generate them on behalf of humans and then forget to revoke them. Once a link escapes normal access controls, it can be shared outside the original context, making incident scoping harder and increasing the likelihood of data exposure. The risk rises further when the linked resource contains secrets, operational runbooks, or sensitive customer data, because those assets may support follow-on compromise rather than simple disclosure.
NHIMG research shows that 91.6% of secrets remain valid five days after the targeted organisation is notified, which illustrates how long access can persist after a control failure is known. That persistence matters for public links because revocation delays, weak ownership, and poor visibility often mean the exposure remains live even after detection. Guidance from NIST Cybersecurity Framework 2.0 reinforces the need for access control, monitoring, and timely response, while the Ultimate Guide to NHIs underscores how weak offboarding and visibility create lasting identity risk.
Organisations typically encounter the consequence only after a file is discovered in an external search, a customer forwards the link, or an incident review shows that the share was never retired, at which point public link governance becomes operationally unavoidable to address.
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 and risk surface, while NIST CSF 2.0 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-02 | Public links often expose secrets or bypass NHI access governance. |
| NIST CSF 2.0 | PR.AC | Public links are an access-control and monitoring concern under CSF. |
| NIST Zero Trust (SP 800-207) | SC-7 | Public links can bypass trust boundaries that Zero Trust expects to enforce. |
Inventory externally shared resources and revoke unauthorised links as part of secret and access hygiene.
