Detection rules › Kusto

Valimail Enforce - Unusual Rate of Configuration Changes or User Additions

Status
available
Severity
medium
Time window
1h
Group by
User
Source
github.com/Azure/Azure-Sentinel

This query searches for a single user performing more than 3 configuration changes or user additions within a 1-hour window on any domain. An unusual burst of changes may indicate a compromised admin account, unauthorized automation, or insider threat.

MITRE ATT&CK coverage

Rule body kusto

id: 3cbb78d9-81ac-42c9-b3cd-7e6baea7d9ff
name: Valimail Enforce - Unusual Rate of Configuration Changes or User Additions
description: |
  This query searches for a single user performing more than 3 configuration changes or user
  additions within a 1-hour window on any domain. An unusual burst of changes may
  indicate a compromised admin account, unauthorized automation, or insider threat.
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: ValimailEnforce
    dataTypes:
      - ValimailEnforceEvents_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Impact
  - DefenseEvasion
  - PrivilegeEscalation
relevantTechniques:
  - T1562
  - T1531
  - T1078
query: |
  let threshold = 3;
  let timeWindow = 1h;
  ValimailEnforceEvents_CL
  | where EventCategory in (
      "DMARCPolicy",
      "SPFConfiguration",
      "DKIMConfiguration",
      "DomainManagement",
      "UserManagement"
    )
  | summarize
      ChangeCount       = count(),
      HighValueCount    = countif(IsHighValueEvent == true),
      Domains           = make_set(Subject),
      DomainCount       = dcount(Subject),
      Actions           = make_set(EventType),
      Categories        = make_set(EventCategory),
      FirstSeen         = min(PerformedAt),
      LastSeen          = max(PerformedAt)
    by User, bin(PerformedAt, timeWindow)
  | where ChangeCount > threshold
  | extend
      AccountName   = tostring(split(User, "@")[0]),
      AccountDomain = tostring(split(User, "@")[1]),
      DomainName    = tostring(Domains[0]),
      ChangesPerMin = round(todouble(ChangeCount) / 60.0, 2)
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountDomain
  - entityType: DNS
    fieldMappings:
      - identifier: DomainName
        columnName: DomainName
alertDetailsOverride:
  alertDisplayNameFormat: "Unusual change rate by {{User}}, {{ChangeCount}} changes in 1h across {{DomainCount}} domain(s)"
  alertDescriptionFormat: |
    User '{{User}}' made {{ChangeCount}} configuration changes across {{DomainCount}} domain(s) within one hour.
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: true
    reopenClosedIncident: false
    lookbackDuration: 1d
    matchingMethod: Selected
    groupByEntities:
      - Account
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 3;
let timeWindow = 1h;

Stage 1: source

ValimailEnforceEvents_CL

Stage 2: where

| where EventCategory in (
    "DMARCPolicy",
    "SPFConfiguration",
    "DKIMConfiguration",
    "DomainManagement",
    "UserManagement"
  )

Stage 3: summarize

| summarize
    ChangeCount       = count(),
    HighValueCount    = countif(IsHighValueEvent == true),
    Domains           = make_set(Subject),
    DomainCount       = dcount(Subject),
    Actions           = make_set(EventType),
    Categories        = make_set(EventCategory),
    FirstSeen         = min(PerformedAt),
    LastSeen          = max(PerformedAt)
  by User, bin(PerformedAt, timeWindow)
Threshold
gt 3

Stage 4: where

| where ChangeCount > threshold

Stage 5: extend

| extend
    AccountName   = tostring(split(User, "@")[0]),
    AccountDomain = tostring(split(User, "@")[1]),
    DomainName    = tostring(Domains[0]),
    ChangesPerMin = round(todouble(ChangeCount) / 60.0, 2)

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.

FieldKindValues
ChangeCountgt
  • 3 transforms: cased
EventCategoryin
  • DKIMConfiguration transforms: cased
  • DMARCPolicy transforms: cased
  • DomainManagement transforms: cased
  • SPFConfiguration transforms: cased
  • UserManagement 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.

FieldSource
Actionssummarize
Categoriessummarize
ChangeCountsummarize
DomainCountsummarize
Domainssummarize
FirstSeensummarize
HighValueCountsummarize
LastSeensummarize
Usersummarize
AccountDomainextend
AccountNameextend
ChangesPerMinextend
DomainNameextend