API - Rate limiting

let firstRec = apifirewall_log_1_CL
| where TimeGenerated >= ago(5m) 
| project-away Non_blocking_mode_b, Source_Port_d, Destination_Port_d, Query_s, API_ID_g, Request_Header_s, Response_Header_s, Errors_s, Type, UUID_g
| where Instance_Name_s == "Instance_8" and URI_Path_s has "/api/login" and Status_d == 429;
let rateLimitCount = (toscalar(firstRec | count));
let recCount = iff((rateLimitCount > 20), 1, 0);
firstRec | top recCount by Timestamp_t desc;

tactics:
- Impact
id: b808063b-07d5-432c-95d0-8900da61cce9
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/42Crunch API Protection/Analytic Rules/APIRateLimiting.yaml
status: Available
description: |
    '42Crunch API protection against rate limiting'
version: 1.0.1
severity: Medium
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: Source_IP_s
  entityType: IP
- fieldMappings:
  - identifier: HostName
    columnName: Hostname_s
  entityType: Host
- fieldMappings:
  - identifier: FullName
    columnName: Instance_Name_s
  entityType: Account
kind: Scheduled
name: API - Rate limiting
query: |
  let firstRec = apifirewall_log_1_CL
  | where TimeGenerated >= ago(5m) 
  | project-away Non_blocking_mode_b, Source_Port_d, Destination_Port_d, Query_s, API_ID_g, Request_Header_s, Response_Header_s, Errors_s, Type, UUID_g
  | where Instance_Name_s == "Instance_8" and URI_Path_s has "/api/login" and Status_d == 429;
  let rateLimitCount = (toscalar(firstRec | count));
  let recCount = iff((rateLimitCount > 20), 1, 0);
  firstRec | top recCount by Timestamp_t desc;  
queryPeriod: 5m
eventGroupingSettings:
  aggregationKind: SingleAlert
queryFrequency: 5m
triggerOperator: gt
customDetails: 
requiredDataConnectors:
- connectorId: 42CrunchAPIProtection
  dataTypes:
  - apifirewall_log_1_CL
relevantTechniques:
- T1499