Please do not open a public issue for security problems.

Report privately through GitHub Security Advisories. Include what you found, how to reproduce it, and the impact you think it has. You will get an acknowledgement within a few days.

Azure VM Scheduler starts and stops virtual machines. Treat an instance of it as a privileged system: whoever controls it can power down production.

Because of that, the defaults are deliberately restrictive:

• Both action gates ship off. ENABLE_REAL_AZURE_STARTS and ENABLE_REAL_AZURE_STOPS are false in the deployment template. Until an operator turns one on, every wave runs against a deterministic mock adapter and touches nothing in Azure.
• The gates are separate on purpose. A wrong start costs money; a wrong stop causes an outage. Enabling starts never enables stops.
• Each gate is ANDed with a per-tenant permission. A global gate alone is not sufficient — the Azure connection must also permit that action, and a connection marked read-only can never do either.
• never_stop on a virtual machine or any ancestor group removes it from every stop wave and from on-demand stops.
• On-demand stops require an exact confirmation count before they run.

• Azure client secrets and certificates are encrypted at rest with Fernet (AES-128-CBC + HMAC-SHA256) and are never returned to the browser.
• The encryption key comes from FERNET_KEY when set; the Azure template supplies it as a Container App secret. Otherwise a key is generated once into the data directory.
• Prefer managed identity: deploy with the template's system-assigned identity, add an Azure tenant using the default_chain auth method, and grant that identity only the rights it needs. Nothing is then stored at all.
• Passwords are hashed with Argon2. Sessions are database-backed and revocable, cookies are HttpOnly and Secure in production, and every mutating request requires a CSRF token.

Grant reader on the scope you want to manage, plus a custom role limited to the actions the scheduler actually performs:

Microsoft.Compute/virtualMachines/start/action
Microsoft.Compute/virtualMachines/deallocate/action
Microsoft.Compute/virtualMachines/powerOff/action

Virtual Machine Contributor also works but grants far more than this application needs.

The latest published image tag receives security fixes.