Persistent Office 365 Cookie Login

Web Security, Firefox, Software Development, Scripting, Web Development, Office 365, Encryption, Security, Technical Documentation, Microsoft 365 · My team at Brand Vibe spends a lot of time re-entering passwords each time we open Outlook on the web. What I need is a small, secure utility that stores a long-lived authentication cookie locally so our Windows-based staff can jump straight into Office 365 mail on any major browser—Chrome, Edge, or Firefox—without typing credentials over and over again.

Here is what I have in mind:

• A lightweight script, extension, or helper file that captures the valid Micro soft 365 session cookie after the first successful login and then re-injects it on subsequent visits. • Full compatibility with Windows 10/11 and smooth operation in the latest versions of Chrome, Edge, and Firefox. • Clear instructions so my non-technical staff can install, revoke, or refresh the cookie whenever we change a password or need to wipe machines. • Security best practices baked in: the cookie must be stored only on the local machine, encrypted if feasible, and never transmitted to third parties. • A brief walkthrough showing how your solution handles different sign-in flows, given that I’m not sure whether our tenant is currently using any Microsoft SSO enhancements.

Acceptance criteria 1. I can log