How to Protect Microsoft 365 from On-Premises Attacks?
Matthew Tinney
A Focused, Compassionate Visionary, Father of Twin Boys. We help Information Technology engineering teams solve for problems they don't have the DNA to solve because they don't have the people, technology or process.
Microsoft 365 is diverse enough to enrich the capabilities of many types of private businesses. It complements users, applications, networks, devices, and whatnot. However, Microsoft 365 cybersecurity is often compromised and there are countless ways that have been reported so far. One of the hottest gateways to these attacks on Microsoft 365 is through on-premises infrastructure.?
Microsoft 365 is to an organization what the nervous system is to your body. If your on-premises infrastructure is vulnerable, you need to protect this ‘nervous system’ from the lurking security threat.
How do I protect Microsoft 365 from On-Prem Attacks?
You need to carefully configure your infrastructure to protect your Microsoft 365 cloud environment from on-premises compromise:
Why On-premises Infrastructure Provide Avenue for Cyber Attack?
Organizations are usually super sensitive about Microsoft 365 Security . So, for critical authentications and directory object state management settings, they prefer to keep these settings on on-prem infrastructure. A hybrid environment can facilitate them to connect M365 to their on-prem infrastructure. This combination is vital for trust delegation as they can keep any critical settings nearby.
However, if the on-premises environment is compromised, it can be a huge security lapse for your Microsoft 365 security. This will expose potential vulnerabilities in the system. The security flaws are generally about federation trust relationships and account synchronization.
We’ll talk about them in detail as we move forward.
What Are the Main Sources of On-Prem Threats for Microsoft 365?
The two primary avenues of risk are:
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Let’s discuss both of these…
Federation Trust Relationships
They allow users to authenticate to cloud-based applications using their on-premises Active Directory credentials. FTRs do that by establishing a trust relationship between the on-premises identity provider (IdP) and the Cloud-based service provider (SP).
They allow attackers unlimited administrative access to your cloud resources. For instance, FTRs like Security Assertions Markup Language (SAML) authentication can authenticate users in Microsoft 365 via your on-premises identity infrastructure. If the SAML token-signing certificate is compromised, this opens the door for anyone possessing that certificate to impersonate cloud users.
As a precaution, you can disable federation trust relationships for authenticating in Microsoft 365 when feasible.
Account Synchronization
Account synchronization means copying user accounts and other objects from an on-prem identity hub to cloud. This is typically done using a directory synchronization tool, such as Azure AD Connect.
Account synchronization can be a point of concern because it can be used to manipulate privileged users and groups with administrative privileges within Microsoft 365. To mitigate this risk, it’s recommended to ensure that synchronized objects possess no privileges beyond being a standard user in Microsoft 365. You can manage these privileges either directly or by inclusion in trusted roles or groups. Be certain that these objects have no direct or nested assignments within trusted cloud roles or groups.