Quiz Entry - updated: 2026.07.14
What does "fail securely" mean? Give examples.
When something breaks, default to the safe state — deny access rather than allow it. When in doubt, deny.
When something goes wrong, default to a secure state — deny rather than allow.
Examples:
| Scenario | Fail Securely | Fail Insecurely |
|---|---|---|
| Auth service down | Deny all access | Let everyone in |
| Input parsing error | Reject the request | Process partial data |
| Can't determine permissions | Deny the action | Default to admin |
| Application crash | Log users out | Leave sessions active |
| Firewall crash | Block all traffic | Let traffic through |
Principle: When in doubt, deny. It's better to inconvenience legitimate users temporarily than to allow unauthorized access.