NGINX - Multiple user agents for single source

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Id	83a0b48f-1cb7-4b4f-a018-23c3203a239b
Rulename	NGINX - Multiple user agents for single source
Description	Detects requests with different user agents from one source in short timeframe.
Severity	Medium
Tactics	InitialAccess
Techniques	T1190 T1133
Required data connectors	CustomLogsAma
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
Version	1.0.2
Arm template	83a0b48f-1cb7-4b4f-a018-23c3203a239b.json

KQL

let threshold = 5;
NGINXHTTPServer
| summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
| extend ua_count = array_length(set_HttpUserAgentOriginal)
| where ua_count > threshold
| extend IPCustomEntity = SrcIpAddr

YAML

name: NGINX - Multiple user agents for single source
id: 83a0b48f-1cb7-4b4f-a018-23c3203a239b
description: |
    'Detects requests with different user agents from one source in short timeframe.'
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
  entityType: IP
version: 1.0.2
triggerOperator: gt
query: |
  let threshold = 5;
  NGINXHTTPServer
  | summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
  | extend ua_count = array_length(set_HttpUserAgentOriginal)
  | where ua_count > threshold
  | extend IPCustomEntity = SrcIpAddr  
tactics:
- InitialAccess
kind: Scheduled
queryFrequency: 1h
severity: Medium
queryPeriod: 1h
requiredDataConnectors:
- dataTypes:
  - NGINX_CL
  connectorId: CustomLogsAma
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
relevantTechniques:
- T1190
- T1133

ARM