How should security teams handle exposed credentials during M&A due diligence?

Why This Matters for Security Teams

Exposed credentials discovered during M&A due diligence should be treated as inherited identity risk, not as a cleanup task for later. In a transaction, those secrets may already be in attacker hands, embedded in CI/CD, or tied to accounts that bypass normal joiner-mover-leaver controls. Guidance from the OWASP Non-Human Identity Top 10 and the Guide to the Secret Sprawl Challenge both point to the same operational reality: detection is only the first step, because exposed secrets remain usable until revoked or rotated.

This matters because diligence often focuses on financial and legal risk while identity exposure is left underexamined. That gap is especially dangerous when acquired environments include service accounts, API keys, or admin tokens with broad reach across cloud, SaaS, and source control systems. Current guidance suggests teams should assume any disclosed secret may already be replayed, copied, or embedded in automation outside the seller’s direct control.

In practice, many security teams encounter credential abuse only after integration begins, rather than through intentional pre-close identity verification.

How It Works in Practice

The right response is to build a credential triage workflow into the deal process itself. Start by inventorying all exposed secrets, classifying them by privilege, blast radius, and whether they are human or non-human credentials. Then verify each item as early as possible after close, because the window between signing and remediation is where attackers benefit most. NHI-specific guidance from 52 NHI Breaches Analysis shows how often exposed machine credentials become the entry point for broader compromise.

For high-risk exposures, the operational sequence is straightforward:

• Force immediate secret rotation or revocation for anything confirmed or likely exposed.
• Re-enrol MFA where the account is interactive and MFA is still supported.
• Place temporary access restrictions on service accounts until ownership and scope are verified.
• Map every credential to its runtime use, including scripts, pipelines, integrations, and third-party callbacks.
• Preserve evidence for legal and incident response teams while preventing continued use.

Security teams should also align the process with established identity controls. The NIST SP 800-63 Digital Identity Guidelines help frame assurance, authentication, and verifier recovery decisions, while NIST SP 800-53 Rev 5 Security and Privacy Controls provides the control language for access enforcement, auditability, and incident handling.

The practical goal is not just to find secrets, but to determine whether they are still valid, where they are used, and whether the acquired environment can safely operate before trust is expanded. These controls tend to break down when secrets are buried in unmanaged automation, because ownership is unclear and revocation can disrupt business-critical workloads.

Common Variations and Edge Cases

Tighter secret handling often increases deal friction and remediation cost, requiring organisations to balance acquisition speed against the risk of inherited compromise. That tradeoff is real, especially when the seller lacks complete asset inventory or when legacy systems cannot tolerate immediate credential rotation.

There is no universal standard for this yet, but current guidance suggests a risk-based approach. Low-privilege secrets with short TTLs may be rotated in batches after close, while admin tokens, CI/CD credentials, and secrets tied to external integrations should be treated as urgent blockers. Long-lived static credentials are the worst case, since they can survive beyond the transaction and remain valid in places neither side fully controls.

Edge cases also appear when exposed credentials belong to contractors, shared mailboxes, or federated platforms. In those environments, a password reset alone may not be enough, because the real issue is access propagation across connected systems. The best practice is evolving toward complete dependency mapping, not just account-level cleanup.

For teams looking to benchmark their maturity, the 2024 Non-Human Identity Security Report shows why this work is often underprepared: only 19.6% of professionals report strong confidence in secure NHI management, and 88.5% say their NHI practices lag human IAM. In acquisition scenarios, that gap becomes a live security issue, not a theoretical one.

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