| name | scc-security |
| description | Review OpenShift Security Context Constraints for correct privilege levels. Use when auditing pod security, reviewing SCC assignments, or configuring container runtime permissions on OpenShift clusters.
|
| metadata | {"category":"secure_development","subcategory":"kubernetes"} |
OpenShift Security Context Constraints (SCC)
SCCs control what actions pods can perform and what host resources they can access. If no security context is specified, OpenShift applies the restricted SCC by default.
What SCCs Control
- Privileged container execution
- Linux capabilities requested by containers
- Host directory volume mounts
- SELinux context
- Container user and group IDs
- Host namespace and networking access
- FSGroup ownership of volumes
- Supplemental groups
- Read-only root filesystem requirement
- Volume types
- Seccomp profiles
SCC Reference
| SCC | Description | When to Use |
|---|
| restricted | Denies all host features; requires namespace-allocated UID and SELinux label. Most restrictive. | Default for all workloads; prefer this unless a specific relaxation is justified |
| nonroot | Like restricted, but allows any non-root UID | When the container must run as a specific non-root UID |
| anyuid | Like restricted, but allows any UID/GID | When the container requires a specific UID (including root UID without root privileges) |
| hostnetwork | Allows host networking and ports; requires namespace UID/SELinux | Only for pods that must bind to host network interfaces |
| hostaccess | Allows all host namespaces; requires namespace UID/SELinux | Only for trusted pods requiring host namespace access |
| hostmount-anyuid | Like restricted, but allows host mounts and any UID | Only for pods requiring host filesystem access (e.g., persistent volume recycler) |
| privileged | Full access to all host features; any user, group, SELinux context | Only for cluster administration requiring maximum access |
| node-exporter | Purpose-built for the Prometheus node exporter | Only for the node exporter DaemonSet |
| custom | Administrator-defined constraints | Requires careful security review; document every relaxation |
Security Review Guidelines
- Start from restricted and relax only when a specific capability is justified
- Document why a workload cannot run under restricted
- Custom SCCs require particular scrutiny: every relaxation from restricted must have a documented rationale
- Review that SCCs are bound to the correct ServiceAccounts, not overly broad groups
- Verify that no workload uses privileged SCC unless it is a cluster administration component
- Check that
runAsNonRoot: true is set unless the container requires root to function
- Check that
readOnlyRootFilesystem: true is set unless the container must write to its root filesystem
Implementation Checklist
References
