Mythos-class AI doesn't need a zero-day to get into your tenant. It uses the defaults, exceptions and forgotten grants every tenant builds up over time: a "temporary" Conditional Access exclusion, an app that still holds permissions from a finished project, or a Copilot Studio agent whose maker has left the company.
Written by 17x Microsoft MVP Kanwal Khipple, this playbook boils Mythos-era readiness down to three questions every security leader should be able to answer with evidence, not assumptions. It then gives your team the tables, checklists and 90-day plan to close the gaps.
What's Inside the Mythos-Ready Microsoft 365 Playbook?
- The Three Questions Framework: Can we stop risky agents? Is the tenant configured the way we think? Is every app and agent vetted?
- 12 Misconfigurations AI Attackers Chain Together: What each one is, why it matters, where to check it and how to fix it
- Agent Risk Prioritization Table: Seven risk signals that move a Copilot Studio agent to the top of your fix list
- App & Agent Vetting Checklist: A gate for new requests and a lens for reviewing what's already approved
- The 12-Step, 90-Day Plan: Three 30-day waves: Close the Doors, Cut Standing Access, Make It Continuous
- 15-Minute Self-Assessment Scorecard: Find out whether your tenant is well defended, exposed or high risk
- Before, During & After Attack Playbook: Controls for each phase, plus the evidence your board should expect to see
Why Microsoft 365 Security Readiness Matters Now
The Exposure Window Is Closing
For two decades, attacks were slow enough that defenders had time to notice and respond. AI that reasons like a penetration tester can shrink weeks of reconnaissance into hours. Quarterly reviews and human-speed triage can't keep up.
Microsoft 365 Is a Concentrated Target
One Entra ID tenant controls Exchange, SharePoint, OneDrive, Teams, Power Platform and Copilot. Copilot and agents surface whatever a compromised identity can reach, and an attacker can query it in plain language. Every Copilot rollout raises the value of a single compromised account.
You Don't Need New Tools. You Need Fewer Unexamined Defaults.
Most of the exposure sits in settings you already control, using licenses you already pay for. The 90-day plan relies on controls most Microsoft 365 E3 and E5 tenants already own. The goal isn't to be perfect. It's to be unchainable.
Who This Playbook Is For
- CISOs and security leaders who need a board-ready way to set direction and report progress
- IT directors rolling out Copilot, Copilot Studio agents or Power Platform
- Microsoft 365 and Entra ID administrators who need checklists they can act on
- Power Platform and SharePoint owners responsible for makers, environments and sharing
It's written for leaders as well as operators. Each section starts with the business case before moving to the controls.
What You'll Learn
- What Mythos-class AI is and why it changes the economics of attacks on Microsoft 365
- How a five-step chained attack moves from a phishing code to silent data exfiltration, and where to break the chain
- How to inventory, own and stop risky Copilot Studio agents, flows and connectors without slowing makers down
- Which board metrics prove progress: ownerless agents, over-privileged apps, configuration drift and time to contain
- How to pre-approve containment so response happens in minutes, not meetings
Get Your Mythos-Ready Microsoft 365 Playbook
Most leadership teams believe their tenant is in better shape than it really is, because policies are visible and exceptions aren't. Download the playbook, take the scorecard and see where you actually stand.
