kqlMITfrom Azure/Azure-Sentinel

Conditional Access Policy Modified by New User

'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'

Quality

FP risk

—

Forks

Views

ATT&CK techniques

T1078.004

Rule sourceDetections/AuditLogs/ConditionalAccessPolicyModifiedbyNewUser.yaml

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