API - Rate limiting

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Id	c6258d51-7b82-4942-8293-94c1dcf91595
Rulename	API - Rate limiting
Description	42Crunch API protection against first-time access
Severity	Low
Tactics	Discovery InitialAccess
Techniques	T1087 T1190
Required data connectors	42CrunchAPIProtection
Kind	Scheduled
Query frequency	5m
Query period	5m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/42Crunch API Protection/Analytic Rules/APIFirstTimeAccess.yaml
Version	1.0.1
Arm template	c6258d51-7b82-4942-8293-94c1dcf91595.json

KQL

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_9" and URI_Path_s has "/api/login" |
top 1 by Timestamp_t desc;
let ipAddress = toscalar(firstRec | summarize by Source_IP_s);
let secondRec = apifirewall_log_1_CL
| where TimeGenerated >= ago(7d) 
| 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_9" and URI_Path_s has "/api/login" and Source_IP_s == ipAddress;
let recCount = iff((toscalar(secondRec | count) > 1), 0, 1);
secondRec | take recCount

YAML

queryPeriod: 5m
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_9" and URI_Path_s has "/api/login" |
  top 1 by Timestamp_t desc;
  let ipAddress = toscalar(firstRec | summarize by Source_IP_s);
  let secondRec = apifirewall_log_1_CL
  | where TimeGenerated >= ago(7d) 
  | 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_9" and URI_Path_s has "/api/login" and Source_IP_s == ipAddress;
  let recCount = iff((toscalar(secondRec | count) > 1), 0, 1);
  secondRec | take recCount  
name: API - Rate limiting
entityMappings:
- fieldMappings:
  - columnName: Source_IP_s
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: Hostname_s
    identifier: HostName
  entityType: Host
- fieldMappings:
  - columnName: Instance_Name_s
    identifier: FullName
  entityType: Account
eventGroupingSettings:
  aggregationKind: SingleAlert
queryFrequency: 5m
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/42Crunch API Protection/Analytic Rules/APIFirstTimeAccess.yaml
description: |
    '42Crunch API protection against first-time access'
kind: Scheduled
version: 1.0.1
status: Available
severity: Low
requiredDataConnectors:
- connectorId: 42CrunchAPIProtection
  dataTypes:
  - apifirewall_log_1_CL
triggerOperator: gt
triggerThreshold: 0
customDetails: 
tactics:
- Discovery
- InitialAccess
id: c6258d51-7b82-4942-8293-94c1dcf91595
relevantTechniques:
- T1087
- T1190

ARM