Why does privileged account reduction matter during mergers and acquisitions?

Why This Matters for Security Teams

During mergers and acquisitions, privileged account reduction is not just an access-review exercise. It is a control to shrink the number of inherited identities that can be abused while systems, directories, and trust relationships are still being rationalised. That matters because M&A environments usually contain duplicated admins, stale local accounts, and exceptions created for speed. NHI Mgmt Group notes that 97% of NHIs carry excessive privileges, which is especially dangerous when two organisations’ control planes are being combined. See the Ultimate Guide to NHIs — Key Challenges and Risks and the OWASP Non-Human Identity Top 10 for why over-privileged service access is so frequently missed.

Security teams often underestimate how fast inherited privilege becomes a liability. The issue is not only human admins; service account, break-glass users, API keys, and directory sync accounts can all survive long after the original business justification has disappeared. In practice, many security teams encounter privilege sprawl only after a directory merge, cloud migration, or incident review has already exposed who still has standing access.

How It Works in Practice

Effective privileged account reduction in M&A starts with inventory, then rapidly moves to classification and removal. The practical goal is to identify every privileged identity across both organisations, determine whether it is still needed for integration, and collapse it into a smaller set of governed access paths. This includes domain admins, local administrators, application service accounts, CI/CD credentials, and emergency access accounts. The Ultimate Guide to NHIs — Key Challenges and Risks is useful here because inherited NHI sprawl often hides inside tooling and automation rather than just user directories.

Best practice is to pair reduction with explicit justification. If an account cannot be removed immediately, it should be time-bound, monitored, and tied to a named owner. Current guidance also favours separating standing privilege from task-based privilege wherever possible. For example, privileged access management, just-in-time elevation, and short-lived credentials reduce the blast radius when integration teams need temporary admin rights. That approach aligns with the OWASP Non-Human Identity Top 10, which treats excessive permission scope and poor lifecycle controls as core risks.

• Inventory privileged identities across both entities before directory consolidation.
• Remove duplicate admins and convert permanent elevation into just-in-time access where feasible.
• Require ownership, business purpose, and expiry for every remaining privileged account.
• Review non-human identities alongside human admins because automation often retains standing access.

These controls tend to break down when legacy applications require hard-coded local admins or when integration deadlines force exceptions that are never revisited.

Common Variations and Edge Cases

Tighter privileged account reduction often increases integration overhead, requiring organisations to balance speed of consolidation against operational continuity. That tradeoff is real during M&A, especially when one side runs old on-premises directories and the other relies on cloud-native identity controls. In those environments, the right answer is often staged reduction rather than immediate elimination.

There is no universal standard for this yet, but current guidance suggests treating exceptions as temporary by default. Break-glass accounts may remain necessary for incident response, and some regulated systems may require segregated admin paths until cutover is complete. The risk is that temporary access becomes permanent because no one owns the cleanup. A second edge case is third-party and transition-service access: consultants, migration vendors, and managed service providers often inherit more privilege than internal staff because they need rapid access to unstable systems.

Security leaders should also avoid assuming that fewer privileged accounts automatically means better control if logging, approval, and revocation are weak. Reducing accounts without improving monitoring simply narrows the list of suspects while leaving the same abuse paths intact. The strongest programmes reduce privilege, add review discipline, and ensure every exception has an expiry.

Related resources from NHI Mgmt Group

• Why does just-in-time access matter for privileged access management programmes?
• Why do dashboards matter in NHI governance?
• Why do application testing tools matter for NHI governance?
• Why do Shai Hulud style attacks matter to NHI governance?