Audit and Update Old Infrastructure

Legacy infrastructure often becomes a blind spot in otherwise secure systems.

New security controls assume:

• modern kernels,
• updated runtimes,
• predictable behavior.

Old components quietly break those assumptions.

Common Real-World Examples

• Old kernels blocking eBPF-based security tools
• Legacy container runtimes missing security flags
• Outdated base images incompatible with new mitigations
• Unsupported OS versions silently skipping patches

Practical Checks to Run Regularly

# check kernel version (critical for modern security tooling)
$ uname -r

# list nodes and their OS / kernel details
$ kubectl get nodes -o wide

For container images:

# scan for outdated base images and known CVEs
$ trivy image myapp:latest

The Lesson

Security isn't only about adding new defenses.
It's also about removing or upgrading what undermines them.

Quiet systems can still be dangerous — especially when everyone assumes they're safe.

Exercise

1. How old is your base image?
2. Are you using a base image that lies in a repo and is built once every five years? If so, consider creating scheduled CI jobs to check it for vulnerabilities and rebuild it regularly.