A practical walkthrough of securing Microsoft 365 for fintech, from Entra ID to Intune and Conditional Access.
Why fintech tenants outgrow “default” Microsoft 365
Most fintechs I talk to live inside Microsoft 365. Email, documents, Teams calls, board packs, customer data extracts, the lot. It has quietly become one of their most important financial systems, even if nobody ever wrote that down explicitly in a risk register. The problem is, a lot of those tenants were set up quickly in the early days, when the priority was getting everyone an email address and a collaboration space, not satisfying future auditors.
Fast forward a few years and you have a successful product, dozens or hundreds of staff, and perhaps even a banking or e-money licence. Suddenly, that scruffy Microsoft 365 tenant is now fully in scope when regulators, investors or potential partners start asking awkward questions about security. If you recognise yourself in that description, this post is for you. I am not going to pretend that securing Microsoft 365 is an easy afternoon job. As with everything in IT, it is a journey, and it can feel a bit overwhelming when you first look under the covers. You can however get a long way by focusing on a few core areas and being honest about the current state.
First, accept that “default” is not the same as “secure enough for a financial institution”. Microsoft has done a lot of good work to improve the security baseline out of the box, but they still have to balance convenience and security for a very broad customer base. As a fintech handling regulated data, your bar needs to be higher.
Second, stop treating Microsoft 365 as “just email and files”. For many fintechs, it is now where customer communications, internal approvals, identity, and in some cases even workflow automation live. If an attacker gets a foothold there, they get the keys to almost everything that matters.
Third, decide that you are going to treat Microsoft 365 as an investment, not a sunk cost. That means time for a real, governed design, an acceptable budget for licences and tooling where it makes sense, and attention from your senior leadership when you need to make trade offs. The companies that do this well make Microsoft 365 part of their security story, not something they are slightly embarrassed about.
Designing Microsoft 365 around fintech risk and regulation
Once you have admitted that Microsoft 365 is a critical IT system, the next step is to design it with that right level of risk in mind. This always starts with identity.
For fintech and financial services, Entra ID is now your primary security perimeter. Passwords on their own are nowhere near enough. At a minimum, every privileged account should be behind strong multi factor authentication, ideally using phishing resistant methods where you can.
Admin roles should be time bound and approved, not left permanently assigned because “it is easier for support”.
Conditional Access is where all of this comes together. Think of it as the policy engine that decides who can get to what, from where and under which conditions.
On the device side, Intune becomes your friend. A lot of fintechs I speak to are still in a half way house where some devices are enrolled, others are not, and compliance rules are more aspiration than reality. If you are handling regulated data, that is not good enough. You should know which devices are accessing your tenant, whether they are compliant, and be able to block access if they drift out of line.
This is where security baselines are worth their weight in gold. Microsoft, the NCSC and the CIS community have all published baselines for Microsoft 365 and Intune. There is a great overview of these at Practical365’s security baseline article. Even if you do not adopt one in its entirety, use them to calibrate how strict you want to be for different user groups.
Finally, remember that fintech is still financial services in the eyes of the regulator. If you are processing payments, holding client money or handling sensitive customer data, you will be judged by the same sort of expectations around operational resilience and outsourcing as the big banks. That means documenting your Microsoft 365 setup in language your compliance and risk teams actually understand, not just a diagram that only your cloud architect can read.
Give them a clear story: what data lives in Microsoft 365, who has access, how access is granted, how it is monitored, and what you will do if there is an incident. If you cannot tell that story calmly on a bad day, you are not ready on a good day. Alot of this can be achieved by building out your internal processes to make sure HR, IT and Risk are aligned.
Rolling out and maintaining a secure Microsoft 365 setup
Getting to a secure Microsoft 365 environment is one thing. Keeping it that way while your business grows, hires, spins up new products and plugs in new SaaS tools is another. This is where most fintechs quietly drift from “quite well configured” to “we really need to review this” over a couple of years. Nobody deliberately turns off controls, they just bend them slightly to get something shipped, and over time the bends add up.
To avoid that, you need a small number of boring, repeatable habits. First, treat Conditional Access like code. Store your policies in source control, document the intent of each one, and have a proper change process. When someone tweaks a policy to get around a problem, it should be visible and reviewed, not a quiet Friday afternoon change. Second, schedule regular reviews against a baseline. That could be one of the public baselines I mentioned earlier, or mapped against community driven frameworks using Maester. The point is to have something objective to test against, rather than relying on gut feel.
Third, bring your security and engineering teams into the same loop.
New product?
New integration?
New third party plugin that wants “full access to your mailbox”?
None of that should happen without somebody asking how it affects your Microsoft 365 risk. That is not about slowing things down for the sake of it, it is about making sure “move fast and break things” does not become “move fast and leak things”.
Finally, invest in visibility. You cannot defend what you cannot see. Make sure the right logs are being sent to whatever you use for monitoring, whether that is Microsoft’s own tools or a separate SIEM. Configure sensible alerts, not so much noise that everyone just creates inbox rules to ignore them. Do all of that consistently and Microsoft 365 stops being a slightly scary black box and turns into a platform you are genuinely comfortable scaling your fintech on.