Conditional Access Policy Modified by New User

id: 25a7f951-54b7-4cf5-9862-ebc04306c590
name: Conditional Access Policy Modified by New User
description: |
  'Detects a Conditional Access Policy being modified by a user who has not modified a policy in the last 14 days.
    A threat actor may try to modify policies to weaken the security controls in place.
    Investigate any change to ensure they are approved.
    Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-infrastructure#conditional-access'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
queryFrequency: 1d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1078.004
tags:
  - AADSecOpsGuide
query: |
  let known_users = (AuditLogs
    | where TimeGenerated between(ago(14d)..ago(1d))
    | where OperationName has "conditional access policy"
    | where Result =~ "success"
    | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
    | summarize by InitiatingUserPrincipalName);
    AuditLogs
    | where TimeGenerated > ago(1d)
    | where OperationName has "conditional access policy"
    | where Result =~ "success"
    | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
    | extend InitiatingAppId = tostring(InitiatedBy.app.appId)
    | 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 CAPolicyName = tostring(TargetResources[0].displayName)
    | where InitiatingUserPrincipalName !in (known_users)
    | extend NewPolicyValues = TargetResources[0].modifiedProperties[0].newValue
    | extend OldPolicyValues = TargetResources[0].modifiedProperties[0].oldValue
    | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])
    | project-reorder TimeGenerated, OperationName, CAPolicyName, InitiatingAppId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingIPAddress, NewPolicyValues, OldPolicyValues
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: InitiatingUserPrincipalName
      - identifier: Name
        columnName: InitiatingAccountName
      - identifier: UPNSuffix
        columnName: InitiatingAccountUPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAadUserId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: InitiatingIPAddress
  - entityType: CloudApplication
    fieldMappings:
      - identifier: AppId
        columnName: InitiatingAppId
      - identifier: Name
        columnName: InitiatingAppName
version: 1.1.1
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others" ]