They should treat service-to-service and workload-to-workload relationships as governed access paths, not background traffic. That means documenting expected communication, validating whether each path is still needed, and removing trust links that no longer have a clear business or operational purpose.
Why cloud trust links need governance, not just network visibility
Internal cloud relationships are often created to let one workload call another, share data, or trigger a service action. That convenience can hide long-lived trust that no one still owns. IAM and SOC teams should govern those paths as access relationships with scope, purpose, and review, not as passive east-west traffic that only becomes interesting after an incident.
That framing matters because trust in cloud environments is usually expressed through roles, permissions, tokens, certificates, federation, or service policies. Once those relationships outlive the use case that created them, they become standing pathways for misuse, lateral movement, and accidental overreach. A path that is technically “working” may still be unjustified.
What IAM and SOC should document and review first
The first task is to inventory who can talk to whom, under what authority, and for what business purpose. For each service-to-service or workload-to-workload relationship, the record should show the owning team, the expected direction of trust, the authentication method, the allowed environment or account boundary, and the operational reason the link exists.
That documentation needs to be specific enough to support recertification. If a path exists only because it was convenient during a migration, a temporary integration, or a previous architecture, it should not survive unchanged. IAM can own the entitlement and lifecycle view, while SOC uses the same inventory to understand which trust links are normal, which are rare, and which deserve detection rules or investigation playbooks. IAM and IGA Basics is useful here because the control problem is really about entitlement governance, not just connectivity.
At cloud scale, the practical question is not whether the relationship is allowed in principle, but whether it is still justified in production. Paths that cross accounts, environments, or trust domains deserve the same ownership discipline as privileged access, because they can expand blast radius when a workload or secret is compromised. The Cloud Workload Identity Guide is a good reference for thinking about these machine-to-machine trust links as explicit identity constructs rather than ambient infrastructure.
How to reduce standing trust without breaking the business
Good governance starts by validating necessity, then narrowing scope. Teams should confirm whether each relationship is still needed, whether it can be replaced with a narrower authorization model, and whether short-lived credentials or more constrained trust policies can remove persistent dependency. The goal is not to eliminate automation, but to keep only the minimum trust required for the current use case.
That usually means treating overbroad role assumptions, shared service credentials, and reused trust configurations as candidates for removal or redesign. When a trust link is preserved for compatibility, it should be time-bound, clearly owned, and reviewed on a schedule. Cloud PAM and CIEM Guide is relevant because effective permissions and cross-account trust are where excessive cloud access often hides.
In parallel, SOC should tune monitoring around the paths that remain. If a trust link is expected only between two services, then new callers, new regions, unusual timing, or changed error patterns are meaningful signals. This is where cloud trust governance and detection overlap: the governance team defines the approved shape of the relationship, and the SOC team watches for drift from that shape. NIST Cybersecurity Framework 2.0 provides a useful governance-to-detect-to-respond structure for that operating model.
What happens when internal trust relationships are left unowned
Unowned trust paths tend to accumulate quietly. Old integrations remain active after a migration, service identities keep broader permissions than they need, and recurring operational workarounds become de facto production access. The result is not just clutter. It creates hidden privilege, unclear accountability, and attack paths that defenders may never have formally approved.
From a threat perspective, the main risk is that compromise of one workload or one secret becomes enough to move laterally through trusted internal channels. Attackers prefer these paths because they look legitimate, blend into service traffic, and often bypass the scrutiny applied to human access. The same design weakness also complicates incident response, because teams may not know whether a relationship is expected until they have already spent time validating it. ENISA Threat Landscape is a solid external reference for the broader threat context around trust abuse, lateral movement, and supply-chain style exposure.
When teams let internal trust sprawl, they also lose the ability to answer basic questions quickly: who approved the link, what it can reach, and whether it should still exist. That weakens both preventative control and incident triage, which is why governance and monitoring need to be designed together.
Risk and Threat Considerations
Internal cloud trust relationships become a security problem when they outlive the business use case, carry excess privilege, or cross boundaries without active ownership. In that state, they create hidden attack paths that can be abused for lateral movement, privilege expansion, and unauthorized service-to-service access.
Failure mechanism: A workload, role, or token continues to trust another workload after the original purpose has changed, so a compromised service can inherit access that no longer has a clear business justification.
Impact: Attackers gain a legitimate-looking path through internal cloud systems, while defenders inherit larger blast radius, weaker accountability, and slower incident verification.
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 and risk surface, while NIST SP 800-53 Rev 5, NIST CSF 2.0, NIST Zero Trust (SP 800-207) and CSA Cloud Controls Matrix set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-9 — Service Identification and Authentication | Service-to-service trust relationships depend on how non-human actors authenticate. |
| AC-6 — Least Privilege | Internal trust links should only retain the minimum access needed for the service purpose. | |
| Recommendation — Constrain service trust to authenticated, least-privilege identities. Right-size trust relationships to the minimum required permissions. | ||
| NIST CSF 2.0 | GV.AA-01 — Cybersecurity Supply Chain Risk Management | Governance of cloud trust relationships must track third-party and cross-boundary dependencies. |
| ID.AM-01 — Physical devices and systems within the organization are inventoried | Governed trust requires an inventory of systems and service links that exist. | |
| Recommendation — Document and review cross-boundary trust dependencies for risk ownership. Inventory internal service and workload trust paths for ownership and review. | ||
| NIST Zero Trust (SP 800-207) | Zero Trust Architecture | Treating internal trust links as verified access paths aligns with zero trust principles. |
| Recommendation — Assume each internal trust path must be continuously verified and bounded. | ||
| CSA Cloud Controls Matrix | IAM — Identity & Access Management | Cloud trust relationships are governed through cloud IAM, entitlements, and access review. |
| IVS — Infrastructure & Virtualization Security | Cross-service trust in cloud environments depends on controlling the infrastructure paths it traverses. | |
| Recommendation — Apply cloud IAM controls to approve, recertify, and retire trust relationships. Limit infrastructure trust paths that are no longer operationally necessary. | ||
| OWASP Non-Human Identity Top 10 | NHI-01 — Improper Offboarding | Unremoved service relationships are a form of stale non-human access. |
| NHI-05 — Overprivileged NHI | Internal trust links often retain more access than the workload actually needs. | |
| Recommendation — Retire stale non-human trust paths when the business need ends. Remove excess privilege from workload-to-workload trust relationships. | ||
Practitioner Guidance
What to prioritise: Start with trust links that cross accounts, environments, or critical production boundaries, because those relationships usually create the highest blast-radius risk. Then review long-lived service identities, shared credentials, and any integration that no one can currently explain in operational terms.
What to verify: For every active relationship, verify the owner, the consuming workload, the authentication method, the scope of access, and the reason it still exists. If any of those cannot be produced quickly, treat the trust path as a governance gap rather than a harmless connection.
Practitioner takeaway: Govern cloud trust the same way you govern access, because every persistent service relationship is a security decision whether or not anyone labeled it that way.
Related resources from NHI Mgmt Group
- How should security teams govern non-human identities in cloud environments?
- How should security teams govern non-human identities for SOC 2 compliance?
- How should IAM teams govern access when customers, partners, and internal users all share the same trust plane?
- How should security teams prioritise NHI remediation in cloud environments?