Hi!

Attackers want to target service principals because:

• Service accounts and service principals do not have MFA
• Attackers can log into Azure using a service principal account
• These accounts exist with all applications in Azure (most companies have several) 
• These accounts could be controlled through conditional access only with an Azure Active Directory P2.

Sign-in with the service principal using Azure CLI:

az login –service-principal -u YourServicePrincipald -p YourServicePrincipalPassword -tenant YourTenantId –allow-no-subscriptions

To prevent this attack, you can define a Conditional Access policies for your service principals. You need to have an Azure Active Directory Premium P2 to enable this feature.

• https://docs.microsoft.com/en-us/azure/active-directory/conditional-access/workload-identity
• https://docs.microsoft.com/en-us/azure/active-directory/conditional-access/howto-conditional-access-policy-location

Maxime.