Security teams should validate whether delegated Managed Service Accounts, OU permissions, and dMSA-related attributes create an abuse path to privilege escalation. A practical test should look for overly broad CreateChild or GenericAll rights, unrestricted dMSA creation, and the ability to trigger the KDC into issuing privileged PAC content. Safe simulation helps expose the exact kill chain before an attacker does.
How to Test for the Abusability of the BadSuccessor Path
BadSuccessor testing should focus on whether an apparently ordinary Active Directory delegation pattern can be turned into privileged account materialisation. The practical question is not whether a dMSA exists, but whether delegated control over an OU, a managed service account path, or related attributes gives a tester enough influence to induce high-value Kerberos behaviour. That makes this a trust-boundary test: if a lower-privilege principal can shape the inputs that the domain controller accepts, privilege escalation may be reachable without needing a classic password compromise.
Teams should start by validating the exact rights chain on the target OU and any parent objects. If the tester can create child objects, modify sensitive attributes, or apply broad directory rights such as GenericAll, the environment may permit escalation from delegation into impersonation. The point is to prove or disprove whether the directory structure constrains identity creation tightly enough to prevent privilege inheritance from being abused.
For a practical assessment, it is useful to pair directory permission review with controlled simulation of dMSA creation and referral handling. OWASP’s Non-Human Identity Top 10 is relevant here because the test is fundamentally about machine-account authority, not just generic AD hygiene. In practice, many teams discover this weakness only after delegated admin structure has already been used to create a privileged identity path.
What a Safe Validation Flow Should Actually Prove
A sound test should verify three things: whether the tester can create or influence a dMSA, whether the resulting object can be bound into a privileged authentication path, and whether the KDC will issue ticket contents that reflect the escalated privilege. If any one of those links is missing, the escalation path may be incomplete even if the directory permissions look suspicious on paper.
In practice, the best tests are narrowly scoped and reversible. Security teams should use a non-production or tightly governed lab domain that mirrors the target OU structure, then confirm effective permissions rather than relying only on declared ACLs. Overly broad delegation often hides in inherited rights, nested group membership, or administrative convenience objects that were never reviewed after the original rollout. That is why the validation should examine both who can create the object and who can alter the attributes after creation.
- Check whether the test principal can create child objects in the relevant OU.
- Check whether the principal can modify dMSA-related attributes after creation.
- Check whether broad object control such as GenericAll or equivalent effective rights exists.
- Confirm whether ticket issuance reflects the intended privileged context, not just object creation success.
MITRE ATT&CK is useful as a companion reference because the test maps to privilege escalation and credentialed abuse patterns, while the OWASP NHI guidance helps frame the machine-identity side of the abuse path. These controls tend to break down when directory permissions are inherited through complex delegation chains and no one validates the effective rights seen by the KDC.
Where the Test Can Mislead You
Tighter testing often increases operational complexity, because the environment can appear vulnerable even when the full kill chain is not actually reachable. A delegation path may allow object creation but still fail to produce usable privileged tickets if later attribute writes are blocked, if the KDC does not process the object as expected, or if domain hardening reduces the exploitability of the path. That means the test should distinguish “can create the object” from “can translate the object into escalation.”
There is also a genuine trade-off between realism and safety. The more closely a test reproduces the actual abuse chain, the more value it provides, but the greater the need for change control, rollback planning, and clear ownership of the directory objects under review. NIST guidance on access control and auditability remains relevant as a control baseline, but the specific decision point here is whether the environment exposes an abuse path through delegated directory authority rather than simply whether AD is broadly well managed.
If a team only checks for obvious admin groups, it may miss delegated rights that become dangerous once combined with attribute modification or Kerberos ticket behaviour. The most common failure is treating the issue as a static permission review instead of a live proof of exploitability.
Risk and Threat Considerations
BadSuccessor-style abuse matters because it converts delegated directory control into a privilege escalation path that may bypass normal account governance. The risk is not just unauthorized object creation; it is the possibility that a lower-trust operator can shape authentication material in a way that yields elevated access.
Failure mechanism: The weakness materialises when overly broad OU permissions, child-object creation rights, or attribute modification rights let an attacker or insider influence a dMSA workflow and push the KDC toward issuing privileged authentication context.
Impact: The resulting exposure can include unauthorized domain privilege, persistence through a newly created or modified machine identity, and a control gap that is hard to see if teams only audit static ACLs instead of effective abuse paths.
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 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 Non-Human Identity Top 10 | NHI-01 — Secrets and Credential Management | BadSuccessor abuses machine identity and delegated auth material. |
| Recommendation — Restrict dMSA and service-account authority to prevent privilege escalation. | ||
| MITRE ATT&CK | T1068 — Exploitation for Privilege Escalation | The question is a privilege-escalation abuse path in AD. |
| T1098 — Account Manipulation | BadSuccessor depends on manipulating account-like directory objects. | |
| Recommendation — Test whether directory rights can be abused for privilege escalation. Hunt for account and object changes that enable unauthorized access. | ||
| CIS Controls v8 | 6.3 — Access Rights Management | Overbroad delegation and effective rights are the core exposure. |
| Recommendation — Review and remove excessive directory permissions that enable escalation. | ||
| NIST CSF 2.0 | PR.AC-4 — Access Permissions and Authorizations | The issue hinges on least-privilege authorization in AD delegation. |
| Recommendation — Enforce least-privilege access on OU and identity administration rights. | ||
Practitioner Guidance
What to prioritise: Validate the effective rights chain first, not the visible delegation model. If the tester can create or modify a dMSA path in a way that reaches privileged ticket issuance, treat the finding as an escalation candidate even before confirming full exploitation.
What to verify: Confirm that the review covers inherited permissions, nested groups, and post-creation attribute control. The important question is whether directory governance prevents the object lifecycle from becoming an elevation mechanism, not whether the object type is nominally allowed.
Decision rule: If the abuse path depends on broad CreateChild, GenericAll, or similar write authority over a sensitive OU, prioritise containment and permission redesign over cosmetic monitoring changes. Monitoring can help detect misuse, but it does not remove the escalation route.
Practitioner takeaway: The most useful test is the one that proves whether delegated Active Directory authority can be converted into privileged authentication, because that is the boundary attackers will try to cross first.
Related resources from NHI Mgmt Group
- How should security teams reduce Active Directory privilege risk?
- How should security teams test Active Directory forest recovery plans?
- How should security teams test Azure privilege escalation paths?
- How should security teams delegate Active Directory password-related permissions without weakening least privilege?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 10, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
