Secrets stored in environment variables are the quiet backbone of every modern application. They hold API keys, database passwords, encryption tokens, and private certificates—critical data that attackers hunt for first. Yet too often, these variables sit unmonitored, unreviewed, and vulnerable. An environment variable security review is not optional. It is the difference between control and chaos.
The first step is knowing what exists. Map every environment variable across your infrastructure: local dev machines, CI/CD pipelines, staging environments, production servers, and cloud services. Include hidden configuration in containers and serverless functions, not just .env files. Unused or forgotten variables are silent liabilities.
Next, classify them. Group variables by sensitivity—public configuration, low-risk internal values, and high-risk secrets. High-risk variables demand strict security policies: short lifespans, limited scope, and encryption at rest and in transit.
Audit access. Who can read them? Who can change them? Every extra permission is a potential breach point. Rotate keys often, and remove stale variables the moment they lose purpose. Audit logs should capture every change, with alerts for unexpected modifications.