The Secret Life of Azure: The Secret That Everyone Could Read
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Moving toward "secret-less" applications with Azure Key Vault.
Governance & Guardrails
The library was quiet, but Timothy was hovering near the chalkboard, looking uneasy. He had a printout of a configuration file in his hand, and he was staring at a specific line of text.
"Margaret," he said, not looking up, "I think I just realized why the security audit was so short this year. I was looking through the app settings for our new web service, and right there—in plain text—was the connection string for the production database. It’s been sitting there for months. Anyone who can see the app settings can see the password."
Margaret walked over and looked at the page. She didn't look shocked; she looked like she had seen this ghost many times before. "The 'Leaky Setting' syndrome," she said softly. "It’s the most common mistake in the cloud. We treat app settings like a private notebook, but in reality, they are more like a bulletin board."
She picked up the chalk and drew a heavy, reinforced box on the board. Inside, she wrote the words KEY VAULT.
The Centralized Safe
"In Azure," Margaret said, "we never want the 'secret' to live inside the application. We want the application to have a reference to the secret. We put the actual password into the Azure Key Vault—a hardened, centralized safe that is managed separately from the code."
Timothy started sketching the safe in his notebook. "So, instead of the app setting saying Password=12345, it says something like @Microsoft.KeyVault(SecretUri=...)?"
"Exactly," Margaret replied. "The application uses its Managed Identity—the badge we talked about in the beginning—to prove who it is. If the vault recognizes the badge, it hands over the secret just in time for the app to use it. The secret never touches your source code, and it’s never visible in the portal UI."
Secrets, Keys, and Certificates
"Wait," Timothy said, "I see three different sections in the Vault: Secrets, Keys, and Certificates. Do they all do the same thing?"
Margaret shook her head. "They have very different jobs.
- Secrets are for things you can read, like a database password or an API key.
- Keys are for mathematical operations—like encrypting a disk—where you want the Vault to do the math so the key never actually leaves the safe.
- Certificates are for your identity and SSL, where the Vault handles the complexity of renewals so they don't expire unexpectedly."
[Image comparing Azure Key Vault Secrets, Keys, and Certificates]
The Soft-Delete Safety Net
Timothy looked at the diagram. "What if I accidentally delete the Vault? If all our passwords are in there, we’re locked out of everything."
"That’s a real fear," Margaret said, "which is why we always enable Soft-Delete and Purge Protection. If someone deletes a secret or even the entire vault, it isn't actually gone. It goes into a 'holding area' for 90 days. Unless you have a very specific set of high-level permissions to purge it, you can always bring it back."
Putting It into Practice
Timothy looked at his configuration printout and then back at the board. "So, the goal is to make the application 'secret-less.' It shouldn't know the password; it should just know where to ask for it."
Margaret smiled. "Precisely. When you remove the secrets from the code, you remove the risk. You can share your settings, show your configuration, and even let people audit your work without ever worrying that you've handed them the keys to the kingdom."
Key Concepts
- Azure Key Vault: A cloud service for securely storing and accessing secrets, keys, and certificates.
- Secrets: Sensitive strings (passwords, connection strings) that are retrieved by applications.
- Keys: Cryptographic keys used for encryption/decryption where the key material remains protected within the vault.
- Certificates: Managed X.509 certificates used for secure communication (SSL/TLS).
- Access Policies vs. Azure RBAC: Two different ways to grant permission to the vault. The modern recommendation is to use Azure RBAC for a consistent experience.
- Soft-Delete: A feature that allows you to recover deleted vaults and vault objects for a set retention period.
Aaron Rose is a software engineer and technology writer at tech-reader.blog and the author of Think Like a Genius.
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