Conditional Access Policy Modified by New User

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Id	25a7f951-54b7-4cf5-9862-ebc04306c590
Rulename	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
Tactics	DefenseEvasion
Techniques	T1078.004
Required data connectors	AzureActiveDirectory
Kind	Scheduled
Query frequency	1d
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml
Version	1.1.1
Arm template	25a7f951-54b7-4cf5-9862-ebc04306c590.json

KQL

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

YAML

tactics:
- DefenseEvasion
triggerOperator: gt
queryPeriod: 14d
queryFrequency: 1d
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
metadata:
  author:
    name: Microsoft Security Research
  categories:
    domains:
    - Security - Others
  support:
    tier: Community
  source:
    kind: Community
id: 25a7f951-54b7-4cf5-9862-ebc04306c590
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: Address
    columnName: InitiatingIPAddress
  entityType: IP
- fieldMappings:
  - identifier: AppId
    columnName: InitiatingAppId
  - identifier: Name
    columnName: InitiatingAppName
  entityType: CloudApplication
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  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml
tags:
- AADSecOpsGuide
version: 1.1.1
severity: Medium
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'  
name: Conditional Access Policy Modified by New User

ARM