Why do service accounts and IAM users with broad permissions increase persistence risk?

Why This Matters for Security Teams

Broadly scoped service account and IAM users are persistence multipliers because they let an intruder do more than steal data. Once those identities are compromised, they can create new users, grant roles, change policies, add backdoors, and reconfigure infrastructure. That turns a single credential into an administrative foothold that survives simple password resets or token revocation.

This is a recurring pattern in NHI incidents documented by Ultimate Guide to NHIs — Key Challenges and Risks and reinforced by the OWASP Non-Human Identity Top 10, where excessive privilege and weak lifecycle controls consistently amplify blast radius. NHI Management Group research also shows how common this exposure has become: the 2024 ESG Report: Managing Non-Human Identities found that 72% of organisations have experienced or suspect a breach of non-human identities.

The operational mistake is treating service accounts like durable plumbing instead of high-value administrative identities. In practice, many security teams encounter persistence only after an attacker has already used one overprivileged account to quietly expand access and alter controls.

How It Works in Practice

Persistence risk rises when a service account can perform privileged actions that outlive the original compromise. Attackers rarely need to keep the first credential forever. They use it to mint better access, then establish alternate paths that are harder to detect and remove. That can include adding API keys, creating new IAM roles, attaching policies, editing trust relationships, or placing access in infrastructure-as-code that gets redeployed automatically.

Good governance starts by shrinking the authority of each non-human identity to the narrowest task it actually performs. The practical model is least privilege plus short-lived access, not broad standing access. Current guidance from the NIST Cybersecurity Framework 2.0 supports this by emphasizing access control, asset visibility, and continuous risk management rather than one-time permission grants.

• Inventory all service accounts and IAM users, including dormant and inherited identities.
• Remove wildcard permissions, policy-creation rights, and role-assumption chains unless they are explicitly required.
• Prefer workload-scoped credentials and ephemeral tokens over static secrets.
• Monitor for privilege escalation behaviors such as new principals, policy edits, and trust-policy changes.
• Bind each identity to an owner, purpose, and expiration review.

NHI Management Group research on Top 10 NHI Issues and breach-driven analysis in 52 NHI Breaches Analysis consistently show that persistence is rarely created by one secret alone. It is created when that secret has enough authority to become the seed of a new administrative path. These controls tend to break down when legacy automation depends on shared admin-style identities because teams cannot remove privilege without breaking production workflows.

Common Variations and Edge Cases

Tighter privilege often increases operational overhead, requiring organisations to balance blast-radius reduction against deployment friction and support complexity. That tradeoff is real, especially in legacy applications, CI/CD pipelines, and cloud automation where a single identity may currently serve many functions.

Best practice is evolving, but there is no universal standard for how to refactor every long-lived service account. In some environments, the safer path is to split one broad identity into multiple narrowly scoped identities. In others, the better answer is to replace static IAM users with workload identity and just-in-time credentials, so access is issued per task and revoked automatically when the task ends.

There is also a difference between access that is broad by design and access that is broad by accident. Vendor support accounts, break-glass accounts, and platform bootstrap identities may legitimately need elevated privileges, but they should be isolated, heavily monitored, and excluded from routine automation. The moment a broad identity is reused for everyday workloads, persistence risk rises sharply.

That is why this issue is not solved by secret rotation alone. If an attacker can still create access, change policy, or assume another role after rotation, the underlying persistence path remains intact.

Related resources from NHI Mgmt Group

• Why do service-level permissions increase cloud risk?
• When do service accounts become a higher risk than ordinary user accounts?
• Why do mergers and acquisitions increase access risk for service accounts and privileged users?
• Why do fragmented IAM tools increase risk for service accounts and API keys?