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id: d8e9f0a1-b2c3-4d4e-5f6a-7b8c9d0e1f2a
name: "SigninLogs — Attacker in the Middle (AiTM) Token Theft Detected"
version: 1.0.0
kind: Scheduled
description: |
  Detects AiTM proxy attacks (Evilginx, Modlishka) that steal session cookies after MFA. Correlates SecurityAlert 'Anomalous Token' events with AADUserRiskEvents where RiskEventType == attackerinTheMiddle. Requires Entra ID P2. MITRE ATT&CK: T1557 (Adversary-in-the-Middle), T1539 (Steal Web Session Cookie).
severity: High
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - SigninLogs
queryFrequency: PT1H
queryPeriod: P7D
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CredentialAccess
  - Collection
relevantTechniques:
  - T1557
  - T1539
query: |

    // ---- Network Allowlist (exclude trusted IPs / CIDR / ranges) --------------
    let _allow = materialize(union isfuzzy=true (print R="" | take 0), (_GetWatchlist('NetworkAllowlist') | project R = tostring(IPOrRange)) | where isnotempty(R));
    let _allowCIDR  = toscalar(_allow | where not(R matches regex @'^\d+\.\d+\.\d+\.\d+-\d+\.\d+\.\d+\.\d+$') | extend R = iff(R has '/', R, strcat(R, '/32')) | summarize make_list(R));
    let _allowRange = toscalar(_allow | where R matches regex @'^\d+\.\d+\.\d+\.\d+-\d+\.\d+\.\d+\.\d+$' | summarize make_list(R));
    let _ExcludeAllowlistedIPs = (T:(IPAddress:string)) {
        T
        | extend IPAddress = tostring(IPAddress)
        | where array_length(_allowCIDR) == 0 or isnull(ipv4_is_in_any_range(IPAddress, _allowCIDR)) or not(ipv4_is_in_any_range(IPAddress, _allowCIDR))
        | mv-apply _r = _allowRange to typeof(string) on (
            extend _lo = tostring(split(_r,'-')[0]), _hi = tostring(split(_r,'-')[1])
            | extend _inRange = ipv4_compare(IPAddress, _lo) >= 0 and ipv4_compare(IPAddress, _hi) <= 0
            | summarize _anyInRange = max(toint(_inRange)))
        | where isnull(_anyInRange) or _anyInRange == 0
        | project-away _anyInRange
    };
    // ---------------------------------------------------------------------------
    let AnomalousTokenRequestIds =
        SecurityAlert
        | where TimeGenerated > ago(7d)
        | where AlertName == "Anomalous Token"
        | mv-expand todynamic(Entities)
        | project Entities
        | extend RequestId = tostring(Entities.RequestId)
        | distinct RequestId;
    AADUserRiskEvents
    | where TimeGenerated > ago(7d)
    | where RequestId has_any (AnomalousTokenRequestIds)
    | where RiskEventType == "attackerinTheMiddle"
    | join kind=leftouter (
        SigninLogs
        | invoke _ExcludeAllowlistedIPs()
        | where TimeGenerated > ago(7d)
        | project
            UserPrincipalName, CorrelationId,
            Location, AppDisplayName, IPAddress,
            RiskLevelDuringSignIn
      ) on $left.CorrelationId == $right.CorrelationId
    | project
        TimeGenerated,
        UserPrincipalName,
        RiskEventType, IPAddress,
        Location, AppDisplayName,
        RiskLevelDuringSignIn
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserPrincipalName
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPAddress
customDetails:
  AppDisplayName: AppDisplayName
  RiskEventType: RiskEventType
alertDetailsOverride:
  alertDisplayNameFormat: "AiTM Token Theft — {{UserPrincipalName}} from {{IPAddress}}"
  alertDescriptionFormat: "Attacker-in-the-Middle session hijack detected — {{AppDisplayName}} session token stolen post-MFA."
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: true
    reopenClosedIncident: false
    lookbackDuration: PT1H
    matchingMethod: AllEntities
    groupByEntities:
  - Account
  - IP