Service Principal Assigned App Role With Sensitive Access

Severity: medium
Time window: 1d
Group by: AddedPermissions, CorrelationId, InitiatedBy, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, ServicePrincipalDisplayName, ServicePrincipalObjectID
Author: Microsoft Security Research
Source: github.com/Azure/Azure-Sentinel

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

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1078.004` Valid Accounts: Cloud Accounts

Event coverage

Provider	Event
Entra-AuditLogs	Add app role assignment to service principal

Rule body kusto

id: dd78a122-d377-415a-afe9-f22e08d2112c
name: Service Principal Assigned App Role With Sensitive Access
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'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
relevantTechniques:
  - T1078.004
tags:
  - AADSecOpsGuide
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])
entityMappings:
  - entityType: Account
    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: IP
    fieldMappings:
      - identifier: Address
        columnName: InitiatingIPAddress
version: 2.0.0
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Let binding: `permissions`

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"]);

The stages below define let detailsList (the rule's main pipeline source).

Stage 1: `source`

AuditLogs

Stage 2: `where`

| where OperationName =~ "Add app role assignment to service principal"

Stage 3: `mv-expand`

| mv-expand TargetResources[0].modifiedProperties

Stage 4: `extend`

| extend TargetResources_0_modifiedProperties = column_ifexists("TargetResources_0_modifiedProperties", '')

Stage 5: `where`

| where isnotempty(TargetResources_0_modifiedProperties)

Stage 6: `where`

| where TargetResources_0_modifiedProperties.displayName =~ "AppRole.Value" or TargetResources_0_modifiedProperties.displayName =~ "DelegatedPermissionGrant.Scope"

Stage 7: `extend`

| extend Permissions = split((parse_json(tostring(TargetResources_0_modifiedProperties.newValue))), " ")

Stage 8: `where`

| where Permissions has_any (permissions)

References permissions (defined above).

Stage 9: `summarize`

| summarize AddedPermissions=make_set(Permissions,200) by CorrelationId

Stage 10: `join`

| join kind=inner auditList on CorrelationId

Stage 11: `extend` (7 consecutive steps)

| 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)))

Stage 12: `where`

| where displayName == "ServicePrincipal.ObjectID" or displayName == "ServicePrincipal.DisplayName"

Stage 13: `extend`

| extend displayName = case(displayName == "ServicePrincipal.ObjectID", "ServicePrincipalObjectID", displayName == "ServicePrincipal.DisplayName", "ServicePrincipalDisplayName", displayName)

displayName =

ifdisplayName == "ServicePrincipal.ObjectID""ServicePrincipalObjectID"

elifdisplayName == "ServicePrincipal.DisplayName""ServicePrincipalDisplayName"

elsedisplayName

Stage 14: `project`

| project TimeGenerated, CorrelationId, Id, AddedPermissions = tostring(AddedPermissions), InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, displayName, newValue

The stages below run on detailsList (the outer pipeline).

Stage 15: `project`

detailsList
| project Id, displayName, newValue

Stage 16: `evaluate`

| evaluate pivot(displayName, make_set(newValue))

Stage 17: `join`

| join kind=inner detailsList on Id

Stage 18: `extend`

| extend ServicePrincipalObjectID = todynamic(column_ifexists("ServicePrincipalObjectID", "")), ServicePrincipalDisplayName = todynamic(column_ifexists("ServicePrincipalDisplayName", ""))

Stage 19: `mv-expand`

| mv-expand ServicePrincipalObjectID, ServicePrincipalDisplayName

Stage 20: `project-away`

| project-away Id1, displayName, newValue

Stage 21: `extend`

| extend ServicePrincipalObjectID = tostring(ServicePrincipalObjectID), ServicePrincipalDisplayName = tostring(ServicePrincipalDisplayName)

Stage 22: `summarize`

| summarize FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated), EventIds = make_set(Id,200) by CorrelationId, AddedPermissions, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIPAddress, InitiatingUserPrincipalName, InitiatedBy, ServicePrincipalDisplayName, ServicePrincipalObjectID

Stage 23: `extend`

| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`OperationName`	eq	`Add app role assignment to service principal`
`Permissions`	match	`.All` `ChannelMessage.Read` `Chat.Read` `EAS.AccessAsUser.All` `EWS.AccessAsUser.All` `Files.Read` `Group.Read` `Mail.` `Notes.Read` `ReadWrite` `TeamsActivity.Read` `offline_access`
`TargetResources_0_modifiedProperties`	is_not_null	(no value, null check)
`displayName`	eq	`AppRole.Value` `DelegatedPermissionGrant.Scope` `ServicePrincipal.DisplayName` transforms: `cased` `ServicePrincipal.ObjectID` transforms: `cased`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`AddedPermissions`	`summarize`
`CorrelationId`	`summarize`
`EventIds`	`summarize`
`FirstSeen`	`summarize`
`InitiatedBy`	`summarize`
`InitiatingAadUserId`	`summarize`
`InitiatingAppName`	`summarize`
`InitiatingAppServicePrincipalId`	`summarize`
`InitiatingIPAddress`	`summarize`
`InitiatingUserPrincipalName`	`summarize`
`LastSeen`	`summarize`
`ServicePrincipalDisplayName`	`summarize`
`ServicePrincipalObjectID`	`summarize`
`InitiatingAccountName`	`extend`
`InitiatingAccountUPNSuffix`	`extend`

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`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Service Principal Assigned App Role With Sensitive Access

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: `permissions`

Stage 1: `source`

Stage 2: `where`

Stage 3: `mv-expand`

Stage 4: `extend`

Stage 5: `where`

Stage 6: `where`

Stage 7: `extend`

Stage 8: `where`

Stage 9: `summarize`

Stage 10: `join`

Stage 11: `extend` (7 consecutive steps)

Stage 12: `where`

Stage 13: `extend`

Stage 14: `project`

Stage 15: `project`

Stage 16: `evaluate`

Stage 17: `join`

Stage 18: `extend`

Stage 19: `mv-expand`

Stage 20: `project-away`

Stage 21: `extend`

Stage 22: `summarize`

Stage 23: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

Service Principal Assigned App Role With Sensitive Access

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: permissions

Stage 1: source

Stage 2: where

Stage 3: mv-expand

Stage 4: extend

Stage 5: where

Stage 6: where

Stage 7: extend

Stage 8: where

Stage 9: summarize

Stage 10: join

Stage 11: extend (7 consecutive steps)

Stage 12: where

Stage 13: extend

Stage 14: project

Stage 15: project

Stage 16: evaluate

Stage 17: join

Stage 18: extend

Stage 19: mv-expand

Stage 20: project-away

Stage 21: extend

Stage 22: summarize

Stage 23: extend

Indicators

Output fields

Let binding: `permissions`

Stage 1: `source`

Stage 2: `where`

Stage 3: `mv-expand`

Stage 4: `extend`

Stage 5: `where`

Stage 6: `where`

Stage 7: `extend`

Stage 8: `where`

Stage 9: `summarize`

Stage 10: `join`

Stage 11: `extend` (7 consecutive steps)

Stage 12: `where`

Stage 13: `extend`

Stage 14: `project`

Stage 15: `project`

Stage 16: `evaluate`

Stage 17: `join`

Stage 18: `extend`

Stage 19: `mv-expand`

Stage 20: `project-away`

Stage 21: `extend`

Stage 22: `summarize`

Stage 23: `extend`