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Service Principal Assigned App Role With Sensitive Access

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Iddd78a122-d377-415a-afe9-f22e08d2112c
RulenameService Principal Assigned App Role With Sensitive Access
DescriptionDetects a Service Principal being assigned an app role that has sensitive access such as Mail.Read.

A threat actor who compromises a Service Principal may assign it an app role to allow it to access sensitive data, or to perform other actions.

Ensure that any assignment to a Service Principal is valid and appropriate.

Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-applications#application-granted-highly-privileged-permissions
SeverityMedium
TacticsPrivilegeEscalation
TechniquesT1078.004
Required data connectorsAzureActiveDirectory
KindScheduled
Query frequency1d
Query period1d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ServicePrincipalAssignedAppRoleWithSensitiveAccess.yaml
Version2.0.0
Arm templatedd78a122-d377-415a-afe9-f22e08d2112c.json
Deploy To Azure
// Add other permissions to this list as needed
let permissions = dynamic([".All", "ReadWrite", "Mail.", "offline_access", "Files.Read", "Notes.Read", "ChannelMessage.Read", "Chat.Read", "TeamsActivity.Read",
"Group.Read", "EWS.AccessAsUser.All", "EAS.AccessAsUser.All"]);
let auditList = 
AuditLogs
| where OperationName =~ "Add app role assignment to service principal"
| mv-expand TargetResources[0].modifiedProperties
| extend TargetResources_0_modifiedProperties = column_ifexists("TargetResources_0_modifiedProperties", '')
| where isnotempty(TargetResources_0_modifiedProperties)
;
let detailsList = auditList
| where TargetResources_0_modifiedProperties.displayName =~ "AppRole.Value" or TargetResources_0_modifiedProperties.displayName =~ "DelegatedPermissionGrant.Scope"
| extend Permissions = split((parse_json(tostring(TargetResources_0_modifiedProperties.newValue))), " ")
| where Permissions has_any (permissions)
| summarize AddedPermissions=make_set(Permissions,200) by CorrelationId
| join kind=inner auditList on CorrelationId
| 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 InitiatedBy = tostring(iff(isnotempty(InitiatingUserPrincipalName),InitiatingUserPrincipalName, InitiatingAppName))
| extend displayName = tostring(TargetResources_0_modifiedProperties.displayName), newValue = tostring(parse_json(tostring(TargetResources_0_modifiedProperties.newValue)))
| where displayName == "ServicePrincipal.ObjectID" or displayName == "ServicePrincipal.DisplayName"
| extend displayName = case(displayName == "ServicePrincipal.ObjectID", "ServicePrincipalObjectID", displayName == "ServicePrincipal.DisplayName", "ServicePrincipalDisplayName", displayName)
| project TimeGenerated, CorrelationId, Id, AddedPermissions = tostring(AddedPermissions), InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, displayName, newValue
;
detailsList | project Id, displayName, newValue
| evaluate pivot(displayName, make_set(newValue))
| join kind=inner detailsList on Id
| extend ServicePrincipalObjectID = todynamic(column_ifexists("ServicePrincipalObjectID", "")), ServicePrincipalDisplayName = todynamic(column_ifexists("ServicePrincipalDisplayName", ""))
| mv-expand ServicePrincipalObjectID, ServicePrincipalDisplayName
| project-away Id1, displayName, newValue
| extend ServicePrincipalObjectID = tostring(ServicePrincipalObjectID), ServicePrincipalDisplayName = tostring(ServicePrincipalDisplayName)
| summarize FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated), EventIds = make_set(Id,200) by CorrelationId, AddedPermissions, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, ServicePrincipalDisplayName, ServicePrincipalObjectID
| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])
tactics:
- PrivilegeEscalation
triggerOperator: gt
queryPeriod: 1d
queryFrequency: 1d
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
metadata:
  author:
    name: Microsoft Security Research
  categories:
    domains:
    - Security - Others
    - Identity
  support:
    tier: Community
  source:
    kind: Community
id: dd78a122-d377-415a-afe9-f22e08d2112c
relevantTechniques:
- T1078.004
triggerThreshold: 0
kind: Scheduled
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: InitiatingUserPrincipalName
  - identifier: Name
    columnName: InitiatingAccountName
  - identifier: UPNSuffix
    columnName: InitiatingAccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAadUserId
  entityType: Account
- fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAppServicePrincipalId
  - identifier: ObjectGuid
    columnName: ServicePrincipalObjectID
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: InitiatingIPAddress
  entityType: IP
query: |
  // Add other permissions to this list as needed
  let permissions = dynamic([".All", "ReadWrite", "Mail.", "offline_access", "Files.Read", "Notes.Read", "ChannelMessage.Read", "Chat.Read", "TeamsActivity.Read",
  "Group.Read", "EWS.AccessAsUser.All", "EAS.AccessAsUser.All"]);
  let auditList = 
  AuditLogs
  | where OperationName =~ "Add app role assignment to service principal"
  | mv-expand TargetResources[0].modifiedProperties
  | extend TargetResources_0_modifiedProperties = column_ifexists("TargetResources_0_modifiedProperties", '')
  | where isnotempty(TargetResources_0_modifiedProperties)
  ;
  let detailsList = auditList
  | where TargetResources_0_modifiedProperties.displayName =~ "AppRole.Value" or TargetResources_0_modifiedProperties.displayName =~ "DelegatedPermissionGrant.Scope"
  | extend Permissions = split((parse_json(tostring(TargetResources_0_modifiedProperties.newValue))), " ")
  | where Permissions has_any (permissions)
  | summarize AddedPermissions=make_set(Permissions,200) by CorrelationId
  | join kind=inner auditList on CorrelationId
  | 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 InitiatedBy = tostring(iff(isnotempty(InitiatingUserPrincipalName),InitiatingUserPrincipalName, InitiatingAppName))
  | extend displayName = tostring(TargetResources_0_modifiedProperties.displayName), newValue = tostring(parse_json(tostring(TargetResources_0_modifiedProperties.newValue)))
  | where displayName == "ServicePrincipal.ObjectID" or displayName == "ServicePrincipal.DisplayName"
  | extend displayName = case(displayName == "ServicePrincipal.ObjectID", "ServicePrincipalObjectID", displayName == "ServicePrincipal.DisplayName", "ServicePrincipalDisplayName", displayName)
  | project TimeGenerated, CorrelationId, Id, AddedPermissions = tostring(AddedPermissions), InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, displayName, newValue
  ;
  detailsList | project Id, displayName, newValue
  | evaluate pivot(displayName, make_set(newValue))
  | join kind=inner detailsList on Id
  | extend ServicePrincipalObjectID = todynamic(column_ifexists("ServicePrincipalObjectID", "")), ServicePrincipalDisplayName = todynamic(column_ifexists("ServicePrincipalDisplayName", ""))
  | mv-expand ServicePrincipalObjectID, ServicePrincipalDisplayName
  | project-away Id1, displayName, newValue
  | extend ServicePrincipalObjectID = tostring(ServicePrincipalObjectID), ServicePrincipalDisplayName = tostring(ServicePrincipalDisplayName)
  | summarize FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated), EventIds = make_set(Id,200) by CorrelationId, AddedPermissions, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, ServicePrincipalDisplayName, ServicePrincipalObjectID
  | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ServicePrincipalAssignedAppRoleWithSensitiveAccess.yaml
tags:
- AADSecOpsGuide
version: 2.0.0
severity: Medium
description: |
  'Detects a Service Principal being assigned an app role that has sensitive access such as Mail.Read.
    A threat actor who compromises a Service Principal may assign it an app role to allow it to access sensitive data, or to perform other actions.
    Ensure that any assignment to a Service Principal is valid and appropriate.
    Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-applications#application-granted-highly-privileged-permissions'  
name: Service Principal Assigned App Role With Sensitive Access