Evidence Drift

Expanded Definition

Evidence drift is a governance failure where the control objective is present, but the evidence needed to prove it has become incomplete, disconnected, or stale. In NHI environments, that gap is especially common when retrieval, tool execution, policy evaluation, and output generation are recorded in separate systems, with no single chain of custody. NHI Management Group treats this as an assurance problem, not just a logging problem, because a control cannot be credibly demonstrated if its proof trail cannot be reconstructed. This matters under NIST Cybersecurity Framework 2.0 because governance, detection, and recovery depend on evidence that remains timely and attributable.

Definitions vary across vendors, especially in agentic AI products that label telemetry as audit evidence even when it omits prompt context, tool calls, or privileged actions. The operational distinction is that evidence drift is not the same as log loss alone; it also includes evidence that exists but no longer supports the control it was meant to prove. The most common misapplication is treating a retained log stream as sufficient proof when the linked event sequence is fragmented across systems and cannot demonstrate end-to-end execution under the relevant policy.

Examples and Use Cases

Implementing evidence preservation rigorously often introduces retention, correlation, and storage overhead, requiring organisations to weigh audit confidence against platform complexity and cost.

• An AI agent approves a ticket, calls a cloud API, and writes a summary, but the approval record, API trace, and output are stored in different tools with mismatched timestamps, making the control outcome hard to prove.
• A service account rotates successfully, yet the evidence of rotation sits in a vault, the deployment record sits in CI/CD, and the alert closure sits in a ticketing system, leaving the audit trail incomplete.
• A privileged workflow is logged, but the supporting policy version is missing, so investigators cannot show which rule set governed the action at the time it occurred.
• The Salesloft OAuth token breach illustrates how credential misuse becomes harder to investigate when token issuance, access use, and downstream data movement are not tied into one evidentiary record.
• The JetBrains GitHub plugin token exposure shows how exposed secrets can remain operationally dangerous when teams cannot rapidly assemble a complete proof trail for discovery, revocation, and impact analysis.

Why It Matters in NHI Security

Evidence drift weakens incident response, audit readiness, and trust in automated controls. In NHI security, the impact is amplified because machine identities act at scale, often through ephemeral processes, delegated permissions, and distributed tooling. When a service account, API key, or agent action is questioned, teams need to prove who or what acted, under which policy, with which secret, and what evidence shows the action was authorised. If those proof points are stale or split across systems, the organisation may be unable to demonstrate control effectiveness even when the control itself exists.

NHI Management Group research shows that only 5.7% of organisations have full visibility into their service accounts, a visibility gap that makes evidence drift far more likely to persist unnoticed. The risk is not abstract: once evidence cannot be reconstructed quickly, incident handling becomes slower, root cause analysis becomes weaker, and regulatory responses become more fragile. Organisational exposure often becomes obvious only after a breach, audit challenge, or privilege abuse investigation, at which point evidence drift is operationally unavoidable to address.

Related resources from NHI Mgmt Group

• Audit evidence drift
• What evidence is needed to understand the impact of shadow AI agents?
• How should security teams think about a compromised integration like Drift?
• When does just-in-time access help most in DORA evidence collection?