Security teams should prioritize testing the paths that most often lead to unauthorized access: web application compromise, credential abuse, phishing, and denial of service conditions that distract defenders. They should also include internal and supply chain scenarios, because those actors can expose far more records when they succeed. The goal is to validate detection, access controls, and response across realistic breach paths.
Focus test coverage on the paths attackers actually use
Security teams get the most value when they test breach paths that combine realistic initial access with realistic data exposure. That means validating whether an attacker can move from web-facing compromise, reused or stolen credentials, phishing success, or a distracted-response window into sensitive systems and records. The test should answer a practical question: if one of these paths succeeds, do access controls, detection, and escalation handling actually stop or contain the loss?
Start with the highest-probability routes, then make sure the exercise checks the second-order effects that often decide whether a breach becomes a disclosure event. For example, a small foothold in an application can become a broad data event if authorization is weak, logging is sparse, or privileged workflows are reachable from the same path.
- Test whether one compromised account can reach more data than it should.
- Test whether a single phishing success becomes a reusable foothold.
- Test whether alert fatigue or a noisy incident delays containment.
Realistic attack-path testing is also where a web-focused control review becomes more useful than a checklist. An application that passes a scanner may still fail when tested for broken access control, session abuse, or insecure trust between tiers. The same is true of credential paths: a valid login is not a success if it can be replayed, escalated, or reused across environments.
Include internal, third-party, and supply chain scenarios because blast radius changes
Internal compromise often matters because trusted access can reveal far more data than an external probe. Third-party and supply chain paths matter for the same reason: once a partner, support channel, or connected platform is inside the trust boundary, the breach path changes from isolated access to distributed exposure. Teams should therefore test not only perimeter failure, but also what happens when a trusted relationship is abused.
This is where the most useful exercises connect access, trust, and data movement. A supplier account, a service integration, or an over-scoped admin path can turn a contained event into mass exposure if segmentation, least privilege, and monitoring are weak. Good testing asks whether the organisation can detect abnormal use quickly enough to stop data staging or exfiltration before records leave the environment.
NHIMG’s The 52 NHI breaches Report is useful background for the internal and third-party access patterns that often widen a breach. The same is true of breach case studies such as Internet Archive breach and Cisco DevHub NHI breach, which show how exposed tokens, keys, or credentials can become direct access paths.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Agentic AI Top 10 and MITRE ATT&CK address the attack and risk surface, while CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Agentic AI Top 10 | A2 — Unsafe External Interaction | Tests help catch web and phishing paths that let attackers drive unsafe access to sensitive data. |
| A3 — Tool Misuse | Breach-path validation should expose when trusted tools or workflows can be abused to reach data. | |
| Recommendation — Test external interaction paths to ensure untrusted input cannot trigger unauthorized data access. Verify tools and workflows cannot be abused to expand access beyond intended boundaries. | ||
| CIS Controls v8 | 6 — Access Control Management | Testing breach paths depends on least privilege and proper access enforcement across trust boundaries. |
| Recommendation — Review access rights so compromised accounts cannot reach sensitive systems or data unnecessarily. | ||
| MITRE ATT&CK | T1078 — Valid Accounts | Credential abuse is one of the most common breach paths leading to sensitive-data exposure. |
| Recommendation — Hunt for valid-account abuse and validate that compromised logins trigger containment. | ||
| NIST CSF 2.0 | DE.CM — Security Continuous Monitoring | Breach-path tests should confirm the organisation can detect compromise and suspicious access quickly. |
| Recommendation — Exercise monitoring use cases that reveal suspicious access, lateral movement, and exfiltration. | ||
Practitioner Guidance
What to prioritise: Test the breach path, not just the control in isolation. The most useful assessments chain initial access, privilege use, and data access so you can see where containment actually fails.
What to verify: Confirm that a valid credential, a phished session, or a trusted third-party path cannot reach sensitive records without additional checks, and that monitoring triggers before large-scale exfiltration is possible.
What practitioners underestimate: The response side of the exercise is often the differentiator. If defenders cannot triage the event quickly, even a modest foothold can become a high-volume data incident.
Practitioner takeaway: The best breach-path tests prove whether your environment fails closed under realistic attacker movement, not whether each individual control looks strong on paper.
Related resources from NHI Mgmt Group
- How should security teams handle AI interactions that can expose sensitive data in real time?
- How should security teams respond to a data breach when access paths are unclear?
- How should security teams prove whether sensitive data was actually accessed during a breach?
- How should security teams rotate shared integration credentials after a third-party breach exposes access paths into SaaS data pipelines?
