The Slack notification came at 03:12. A bot had pushed code to production without review. Access logs showed permissions no one remembered granting. The breach wasn’t from outside—it came from inside.
Least privilege is how you stop this. In Slack, it means users, bots, and integrations only get what they need—nothing more. Tight scope, minimal surface area, zero unused permissions. You give access for a reason, you end it when the reason is gone.
Slack workflow integration makes this harder than it looks. A single automation can pull, post, and delete. The Slack API uses OAuth scopes; grant the wrong one and a harmless script becomes dangerous. Least privilege in Slack workflows means auditing every scope, keeping tokens short-lived, and assigning roles that match real tasks.
Start with token hygiene. Rotate keys. Use app-level tokens only where absolutely necessary. Store secrets outside Slack, in a locked vault. Test integrations in sandbox channels before production. Review access quarterly, and cut every permission not in use.