Why do wildcard certificates reduce operational overhead without removing the need for certificate governance?

Why This Matters for Security Teams

wildcard certificate are attractive because they collapse many endpoint certificates into one manageable trust object. That reduces issuance, renewal, and inventory work, which is why teams often adopt them when certificate sprawl starts to slow operations. The tradeoff is that the blast radius expands: one private key can authenticate many subdomains, so a single handling mistake affects far more services than a narrowly scoped certificate would. NIST’s Cybersecurity Framework 2.0 is useful here because it frames asset visibility and protective controls as ongoing duties, not one-time setup tasks.

That operational reality is reflected in NHIMG research. In The Critical Gaps in Machine Identity Management report, SailPoint found that only 38% of organisations have automated certificate lifecycle management in place, while 57% lack a complete inventory of their machine identities. Wildcard certificates do not remove that burden. They simply change the shape of it: fewer objects to track, but higher consequences when the one object is exposed, misissued, or silently allowed to expire. In practice, many security teams encounter outage and compromise risk only after a shared certificate has already become a single point of failure.

How It Works in Practice

A wildcard certificate uses a common name or subject alternative name pattern such as *.example.com, allowing one certificate to validate multiple first-level subdomains. This can simplify deployment for environments with frequent service creation, short-lived environments, or many low-risk vanity subdomains. It is especially useful where certificate sprawl creates operational drag, but the services still need consistent TLS coverage. The governance challenge is that the certificate becomes a reusable trust primitive, so ownership, key protection, and renewal discipline matter more, not less.

Good practice is to treat the wildcard as a shared machine identity with a clearly defined scope. That means:

• Maintain an inventory of every service that relies on it, including test and ephemeral environments.
• Protect the private key with strong storage controls, restricted access, and auditable retrieval paths.
• Track renewal dates, validation method, and CA dependencies so expiry does not become a hidden outage risk.
• Review whether some subdomains deserve dedicated certificates because of sensitivity, compliance, or tenant isolation.
• Use certificate deployment automation, but keep approval and revocation decisions under policy control.

The NHIMG Lifecycle Processes for Managing NHIs guidance reinforces this point: lifecycle controls remain necessary even when the certificate count drops. Current guidance suggests that wildcard certificates work best when paired with authoritative inventory, automated renewal, and clear exception handling. They are not a substitute for governance, because the risk moves from certificate volume to certificate concentration. These controls tend to break down in multi-team or multi-tenant environments because ownership of the shared key and its downstream consumers becomes unclear.

Common Variations and Edge Cases

Tighter certificate consolidation often reduces administrative overhead, but it also increases concentration risk, requiring organisations to balance simpler operations against broader compromise impact. That tradeoff becomes sharper in environments with regulated data, customer-facing subdomains, or segmented trust zones. Best practice is evolving here: there is no universal standard for when wildcard certificates are acceptable, so teams need policy decisions tied to service criticality rather than convenience alone.

Some domains are poor candidates for wildcard coverage. Public-facing authentication portals, high-value administrative interfaces, and tenant-specific services may warrant individual certificates to preserve blast-radius containment. Mixed-use environments also need careful validation rules, because a wildcard only covers one label depth and does not automatically fit nested hostnames. For example, *.example.com does not cover a.b.example.com. Security teams should pair this with decisions from the Top 10 NHI Issues research, especially where shared credentials and weak lifecycle ownership are already known pain points.

NHIMG’s 2024 ESG Report: Managing Non-Human Identities shows how often machine identity weaknesses turn into incidents, which is why wildcard certificates should be governed as operational accelerators, not blanket exceptions. The practical test is simple: if one private key failure would be unacceptable, the wildcard should be narrowed, segmented, or replaced with dedicated certificates.

Related resources from NHI Mgmt Group

• How can teams reduce certificate expiry outages without adding manual overhead?
• How should security teams reduce access review fatigue without weakening governance?
• How should teams reduce attack surface in GCP without losing operational speed?
• How can organisations reduce audit friction without weakening governance?