Entra ID conditional access policy modification

Severity: low
Type: alert
Time window: 5m
Match by: user
Author: Google Cloud Security
Source: github.com/chronicle/detection-rules

Detects when an Entra ID conditional access policy has been modified

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1484` Domain or Tenant Policy Modification

Telemetry coverage

Platform	Record / event type
Microsoft 365	Update policy.

Rule body

// Copyright 2025 Google LLC. Licensed under Apache-2.0.

rule entra_id_conditional_access_policy_modification {

  meta:
    author = "Google Cloud Security"
    description = "Detects when an Entra ID conditional access policy has been modified"
    rule_id = "mr_0c3f7309-a3e3-4c80-9b33-12ade9f499f8"
    rule_name = "Entra ID conditional access policy modification"
    tactic = "TA0004"
    technique = "T1484"
    type = "alert"
    platform = "azure"
    data_source = "o365"
    severity = "Low"
    priority = "Low"

  events:
    $cloud.metadata.event_type = "USER_RESOURCE_UPDATE_CONTENT"
    $cloud.metadata.product_event_type = "Update policy."
    $cloud.metadata.product_name = "Office 365"
    $cloud.metadata.vendor_name = "Microsoft"
    $cloud.target.application = "AzureActiveDirectory"
    $cloud.target.resource.attribute.labels.key = "extendedAuditEventCategory"
    $cloud.target.resource.attribute.labels.value = "Policy"
    $cloud.principal.user.userid = $user

  match:
    $user over 5m

  outcome:
    $risk_score = 35
    $event_count = count_distinct($cloud.metadata.id)
    $user_agent = array_distinct($cloud.network.http.user_agent)
    $policy_name = array_distinct($cloud.security_result.detection_fields["target_1"])
    $security_summary = array_distinct($cloud.security_result.summary)
    $target_application = array_distinct($cloud.target.application)
    //$principal_user_userid = array_distinct($group.principal.user.userid)

  condition:
    $cloud
}

YARA-L rule structure

Condition

Fires when at least one $cloud event in the 5m window.

Events

`$cloud` `USER_RESOURCE_UPDATE_CONTENT`

metadata.product_event_type = "Update policy."
target.application = "AzureActiveDirectory"
target.resource.attribute.labels.key = "extendedAuditEventCategory"
target.resource.attribute.labels.value = "Policy"

Match and correlation

Match key: $user (principal.user.userid)
Within: 5m

Outcome

Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.

Field	Expression
`risk_score`	`35`
`event_count`	`count_distinct($cloud.metadata.id)`
`user_agent`	`array_distinct($cloud.network.http.user_agent)`
`policy_name`	`array_distinct($cloud.security_result.detection_fields["target_1"])`
`security_summary`	`array_distinct($cloud.security_result.summary)`
`target_application`	`array_distinct($cloud.target.application)`