Microsoft Sentinel medium experimental kql

Privileged Account Permissions Changed

'Detects changes to permissions assigned to admin users. Threat actors may try and increase permission scope by adding additional roles to already privileged accounts. Review any modifications to ensure they were made legitimately. Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-privileged-accounts#changes-to-privileged-accounts'

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Detection Logic

let admin_users = (IdentityInfo
| where TimeGenerated > ago(2d)
| summarize arg_max(TimeGenerated, *) by AccountUPN
| where AssignedRoles contains "admin" or GroupMembership has "Admin"
| summarize by tolower(AccountUPN));
  AuditLogs
| where Category =~ "RoleManagement"
| where OperationName has "Add eligible member"
| extend TargetUserPrincipalName = tostring(TargetResources[0].userPrincipalName)
| where tolower(TargetUserPrincipalName) in (admin_users)
| extend TargetAadUserId = tostring(TargetResources[0].id)
| extend Group = tostring(TargetResources[0].displayName)
| extend RoleAddedTo = iif(isnotempty(TargetUserPrincipalName), TargetUserPrincipalName, Group)
| extend mod_props = TargetResources[0].modifiedProperties
| extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
| extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
| extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIPAddress = tostring(InitiatedBy.user.ipAddress)
| extend RoleAddedBy = iif(isnotempty(InitiatingAppName), InitiatingAppName, InitiatingUserPrincipalName)
| mv-expand mod_props
| where mod_props.displayName == "Role.DisplayName"
| extend UserAgent = tostring(AdditionalDetails[0].value)
| extend RoleAdded = tostring(parse_json(tostring(mod_props.newValue)))
| extend TargetAccountName = tostring(split(TargetUserPrincipalName, "@")[0]), TargetAccountUPNSuffix = tostring(split(TargetUserPrincipalName, "@")[1])
| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])
| project-reorder TimeGenerated, OperationName, TargetUserPrincipalName, RoleAddedTo, RoleAdded, RoleAddedBy, InitiatingUserPrincipalName, InitiatingAppName

Field Validations

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